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Chem TB Flashcards Unit 3

1) When arterial blood is exposed to air (as in air bubbles in a collection syringe), what sets of changes occur?

PO2 increased, PCO2 decreased, pH increased

2) Uptake of O2 by the blood in the lungs is controlled primarily by:

the PO2 of alveolar air.

3) Quantitative sweat chloride testing remains the standard for diagnostic testing of cystic fibrosis (CF) because:

an amino acid deletion in the CFTR gene resulting in the loss of electrolyte transport across cell membranes can only be detected by sweat testing.

4) The anticoagulant that is considered best for anaerobic collection of an arterial or venous whole blood specimen for blood gas analysis is:

lyophilized heparin.

5) What is a cause of decreased fractional oxyhemoglobin (FO2Hb)?

Conversion of part of hemoglobin to dyshemoglobin

6) An increase in blood pH with a concomitant decrease in PCO2 and a decreased body temperature and 2,3-diphosphoglycerate will cause the oxygen dissociation curve to:

shift to the left.

7) In the Henderson-Hasselbalch equation, the term “pK'” is the:

negative log of the combined dissociation constant for carbonic acid.

8) The PO2 at which the hemoglobin of the blood is half saturated with O2 is referred to as:

P50

9) In regard to the colligative properties of a solution, the addition of solutes to pure solvent will _____ the vapor pressure of that solution compared with pure solvent.

decrease

10) Historically, chloride was measured in blood by spectrophotometry. Now the methods of choice for chloride measurement include ion-selective electrodes and:

coulometric-amperometric titration.

11) A 24-hour-old infant is tested for quantitative sweat chloride because her older brother was diagnosed with cystic fibrosis. After iontophoresis of pilocarpine nitrate and collection of sweat, the sample is analyzed by coulometric titration. The value of the infant’s sweat chloride was 23 mmol/L (reference interval: 29 mmol/L). The next day, the infant’s physician calls the laboratory to report that the infant has difficulty breathing and that the parents report the infant’s skin tasted salty. The physician is considering a diagnosis of cystic fibrosis. What type of error has likely occurred?

The infant was tested at too young of an age for accurate results to be obtained.

12) To stimulate sweating for a quantitative sweat chloride test, _____ is iontophoresed into the skin.

pilocarpine

13) The high extracellular concentration of which cation contributes to the osmotic strength of extracellular fluid?

Sodium

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14) What electrolytes is regulated in part by dietary intake?a. Chlorideb. Potassiumc. Sodiumd. All of the above

D

15) The most common laboratory method of sodium/potassium measurement in a high-throughput automated chemistry analyzer is:

indirect ion-selective electrode measurement.

16) Osmolality is defined as the number of _____ of solution.

moles of osmotic substances per kilogram

17) The “electrolyte exclusion effect” is: an underestimation of electrolyte concentration by indirect ISE methods when hyperproteinemia is present.

18) The correct formula for calculating plasma osmolality is:

1.86 Na (mmol/L) + glucose (mmol/L) + urea (mmol/L) + 9.

19) What statements concerning electrolytes and electrolyte measurement is incorrect?

Whole blood specimens should be stored at 4° C before separation.

20) Which blood gas parameter is most affected by the choice of arterial versus venous blood?

PO2

21) A blood gas parameter is affected by the choice of arterial versus venous blood. What is the reason for the difference in the value of this correctly identified parameter?

PO2 is generally lower in venous blood after O2 is released in the capillaries and higher in arterial blood because this blood has passed through the lungs.

22) Although aqueous fluid control materials are the most commonly used commercial controls for blood gas and pH measurements, what is their main disadvantage?

They are dissimilar to blood by having lower viscosity and surface tension.

23) An instrument that hemolyzes whole blood by sonication then determines total hemoglobin fractions by spectrophotometry and calculation is called a(n):

co-oximeter.

24) The basic methodology used to measure pH, PCO2, and PO2 is:

osmometry.

25) In an individual older than 6 months of age, what laboratory results is usually associated with cystic fibrosis?

Sweat chloride concentration greater than 60 mmol/L

26) A blood sample from an individual with leukemia is submitted for blood gas analysis. The transport of the sample is delayed for approximately an hour before analysis. What affect, if any, will these two variables have on the blood gas analysis results?

Because of leukocyte glycolysis, pH decreases, PCO2 increases, and PO2 decreases.

27) The most commonly measured colligative property of urine or plasma that is tested in the clinical laboratory to determine osmolality is:

the freezing point.

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28) The specimen of choice for measurement of potassium (K+) is plasma because:

platelets release potassium during the coagulation process in a serum sample.

29) The half-life of a protein hormone in plasma is: short, approximately 10 to 30 minutes.

30) What statements concerning steroid hormones is correct?

Steroid hormones are hydrophobic when free and bind to intracellular receptors in the nucleus.

31) The analytical method that provides better analytical sensitivity in hormone detection than other methods such as immunoassay or receptor-based assays is:

tandem mass spectrometry.

32) What protein hormones produces a decrease in blood glucose by causing glucose to enter cells for energy production?

Insulin

33) Considering the classification of hormones by structure, an example of a steroid hormone would be:

cortisol.

34) An example of a protein hormone synthesized in the hypothalamus, with the principal action to control the release of thyroid-stimulating hormone, is:

thyrotropin releasing hormone.

35) What hormones requires a transport protein to move it through the circulation?

Estrogen

36) What statements concerning protein hormones is correct?

A protein hormone, once bound to its receptor, activates adenylyl cyclase, which leads to eventual phosphorylation of other cellular enzymes.

37) A group of hormones produced by the gastrointestinal tract that stimulates insulin secretion from the pancreas and slows the rate of gastric emptying is referred to as:

incretins.

38) What is an effect of increased parathyroid hormone (PTH) secretion from the parathyroid gland in the homeostatic control of serum calcium?

Increased intestinal absorption of calcium

39) As part of homeostatic control by hormones, the metabolism of electrolytes and water balance is controlled in part by the renal system. What hormone synthesized by the kidneys affects water and electrolyte balance?

Renin

40) Calcium concentration in the blood is regulated by what hormones?

Calcitriol and Parathyroid hormone

41) Binding to a receptor at the outer cell membrane to induce phosphorylation via adenylyl cyclase and cAMP of certain intracellular enzymes is a property of which class of hormone?

Protein andAmino acid-derived

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42) The release of thyroid-stimulating hormone (from the pituitary gland) stimulates the release of thyroid hormones from the thyroid gland. When the level of thyroid hormones increases in the circulation, they shut off the release of TSH from the pituitary. This is an example of which type of feedback?

Negative feedback

43) An example of a polypeptide hormone that is part of the complex integrative function of many hormones involved in development of the human organism is:

growth hormone.

44) In the gastrointestinal (GI) tract, dopamine functions as a modulator of the enteric nervous system or as a paracrine substance. What essential enzyme is required for synthesis of dopamine in the dopaminergic system in the GI tract?

Tyrosine hydroxylase

45) In the diagnosis of pheochromocytoma, what hormone is being assessed by measuring urine metanephrine?

Epinephrine

46) A neoplasm considered to be a pediatric cancer that is derived from the neural crest cells of the sympathetic nervous system is referred to as a:

neuroblastoma.

47) Measurement of urinary metanephrine and vanillylmandelic acid (VMA) assesses the amount of hormone secreted by the _____ and is done to detect the presence of _____.

adrenal medulla; pheochromocytoma

48) What substances is measured in urine to determine the presence of a gastroenteropancreatic neuroendocrine tumor in an individual with carcinoid syndrome?

5-Hydroxyindole acetic acid (5-HIAA)

49) In the assessment of equivocal results in pheochromocytoma testing, the clonidine suppression test is used to differentiate between:

adrenal gland and sympathetic nervous system increases in catecholamine synthesis.

50) Pheochromocytomas: are benign in the majority of cases.

51) The amino acid precursor for the neurotransmitter serotonin (5HT) is:

tryptophan.

52) Metabolism of norepinephrine and epinephrine in adrenal chromaffin cells requires the presence of what enzymes for conversion into normetanephrine and metanephrine?

Catechol-O-methyltransferase

53) In the sympathetic component of the autonomic nervous system, norepinephrine acts to:

increase heart rate and blood pressure.

54) Regarding catecholamines, the amino acid from which dopamine is synthesized?

Tyrosine

55) An overnight fast is recommended for individuals being tested for carcinoid syndrome because:

dietary interference, particularly with foods that contain 5-hydroxyindoles, will produce a false increase in plasma 5-HIAA measurement.

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56) The urinary metabolite measured as an indicator of dopamine synthesis is:

homovanillic acid.

57) The rate-limiting step in the biosynthesis of catecholamines is the:

conversion of tyrosine to 3,4-dihydroxyphenylalanine by tyrosine hydroxylase.

58) The use of tricycle antidepressants by an individual may produce incorrect results in the measurement of norepinephrine and normetanephrine during testing for pheochromocytoma. How will results be affected and why?

The results will be falsely elevated because of inhibition of monoamine reuptake.

59) A man visits his physician complaining of hypertension (elevated heart rate and blood pressure), periodic bouts of profuse sweating, and occasional severe headaches. These symptoms are indicative of:

pheochromocytoma.

60) Currently, the most common method of analysis for plasma catecholamines is:

liquid chromatography (LC) with electrochemical (EC) detection.

61) All of the following represent metabolic effects caused by the action of epinephrine secreted from the adrenal gland except:

increased protein synthesis.

62) What statements concerning folic acid is correct? Folic acid deficiency results in megaloblastic anemia.

63) Deficiency of what vitamins will result in decreased heme synthesis?

Pyridoxal phosphate (PLP)

64) What vitamins will aid in the absorption of iron by the intestine?

Vitamin C

65) Absorption of vitamin B12 requires the presence of: intrinsic factor.66) Which vitamin is given to a newborn within minutes of

birth?Vitamin K

67) Scurvy is associated with deficiency of what vitamins? Vitamin C68) What vitamins would be least affected by long periods

of fat malabsorption?Vitamin C

69) The trace element that is important in the stabilization of the surface of a regenerating tooth is:

fluoride.

70) A 65-year-old woman was admitted to the hospital in mild congestive heart failure. She complained of a burning sensation in her calves and feet and of weight loss. Upon admission she appeared confused, depressed, and pale. She had some edema around her ankles. Her lab results were as follows: low hemoglobin and hematocrit, increased RBC size, decreased RBC and WBC count, and hypersegmented neutrophils. All basic chemistry values were normal. Which vitamin should be tested for deficiency?

Vitamin B12

71) A lack of _____ leads to the symptoms observed in vitamin B12 deficiency.

intrinsic factor

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72) What is the common cause of vitamin B12 deficiency? Pernicious anemia73) Trace elements are: inorganic molecules found in

human and animal tissues in milligram per kilogram amounts or less.

74) What specific specimen collection procedures should be observed when assessing zinc deficiency?

Plasma is the specimen of choice to avoid contamination by RBCs, WBCs, and platelets.

75) What trace elements, when combined with an enzyme, is essential for stabilization of extracellular matrixes such as collagen and elastin?

Copper

76) The most commonly used method of analysis for assessing vitamins A, K, and B6 is:

high performance liquid chromatography (HPLC).

77) A 10-year-old girl visits her pediatrician. The physician notes that the girl has immature secondary sex characteristics and small stature. Her mother who has accompanied her complains that the adolescent also exhibits very slow healing of cuts and scrapes and has had some hair loss. Your laboratory has ruled out any inborn error of metabolism and possible cancer. Deficiency of what trace element might be responsible for the stated symptoms?

Zinc

78) What trace elements would be most affected when a hemolyzed sample is used for analysis?

Manganese

79) Activity of what enzymes might be markedly affected by a deficiency of zinc?

Alkaline phosphatase

80) In trace element analysis, the coupling of an analytical procedure with a technique that separates the chemical complexes of individual elements present in any medium is referred to as a(n):

hyphenated technique.

81) Poor dark adaptation or night blindness is associated with:

deficiency of vitamin A.

82) The ease with which iron can move from a reduced form to an oxidized form in its metalloprotein transferrin is important because:

transport of iron in transferrin occurs only in the oxidized state.

83) The vitamin that is an antioxidant that acts as a scavenger for lipid Peroxyl-free radicals and that has a role in RBC protection from hemolysis is:

E

84) The trace element that is thought to mimic insulin because of its activation of the cellular insulin response is:

vanadium.

85) Bilirubin is considered to be the breakdown product of: protoporphyrin IX.86) In blood, bilirubin is unconjugated but is bound to

_____ as it is transported to the liver.Albumin

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87) An 80-year-old patient visits his physician with an elevated serum iron value and a decreased TIBC. The most likely diagnosis in this case is:

hemochromatosis.

88) The most popular assay used to determine iron deficiency anemia is ferritin. What are the ferritin levels in the correctly identified diagnosis in the preceding question compared to normal?

Increased

89) Regarding serum iron analysis, the maximum concentration of iron that transferrin can bind is reflected in what laboratory measurement?

Total iron binding capacity (TIBC)

90) Iron is transported as ferric iron through the plasma by means of:

transferrin.

91) In an individual using progesterone-based oral contraceptives, serum iron _____ and TIBC _____.

increases; increases

92) Regarding the individual using progesterone-based oral contraceptives, would the transferrin saturation be increased, decreased, or not affected?

Increased

93) What statements concerning TIBC is not correct? TIBC is decreased in an iron deficiency anemia.

94) In the initial step of the diazo reaction for direct bilirubin determination:

serum is added to an aqueous solution of caffeine, sodium acetate, and sodium benzoate.

95) What soluble iron-protein complex is the form in which iron is stored in tissues?

Ferritin

96) What is formed by the reduction of unconjugated bilirubin in the intestines, is found in urine, and is further oxidized to form urobilin?

Urobilinogen

97) The major substance formed from the breakdown of hemoglobin when senescent red blood cells are phagocytized by the reticuloendothelial system is:

bilirubin.

98) The most common cause of iron deficiency anemia in children is:

dietary deficiency.

99) What is the percent transferrin saturation given the following data: serum iron 150 g/dL, TIBC 350 g/dL, transferrin 300 mg/dL, and ferritin 65 ng/mL?

43%

100)The inherited disorders caused by an underproduction of certain globin chains are referred to as the:

thalassemias.

101)What sets of laboratory values correctly reflects an iron deficiency state?

Transferrin saturation low, serum iron decreased, TIBC low to normal

102)What is the mutational basis of an “elongation hemoglobin?”

A single base pair mutation or frameshift at either the 3' end of exon 3 or the 5' end of exon 1 of the alpha2 or beta globin chain

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103)A patient presents with yellowish skin and eyes, fatigue, and mild motor system dysfunction. Upon assessment in the laboratory, the total bilirubin concentration was shown to be 3.0 mg/dL (normal 0.2-1.0 mg/dL) with negative urinary bilirubin. Liver function tests are normal. The most likely diagnosis in this case would be:

Gilbert syndrome.

104)High levels of unconjugated bilirubin that accumulate in the brain are called:

kernicterus.

105)The oxidation of the Fe+2 of hemoglobin to the Fe+3 of methemoglobin by ferricyanide is the initial step in the:

cyanmethemoglobin method of hemoglobin determination

106)In a certain hemoglobin structural variant, a deletion in the coding gene results in a reduction of the production of the beta globin chain. This will result in:

decreased quantity of HbA.

107)Increased total iron in serum is common in all of the following except:

chronic inflammation.

108)The two pairs of globin chains in normal HbA hemoglobin are:

alpha and beta.

109)In hemoglobin F, which globin chains are different from adult hemoglobin chains and what replaces them in the adult?

Gamma chains are replaced by betas.

110)A group of compounds containing four monopyrrole rings connected by methane bridges is the:

porphyrins.

111)A deficiency of the enzyme hydroxymethylbilane synthase (HMBS) results in what acute porphyrias?

Acute intermittent porphyria (AIP)

112)An individual visits his physician with porphyria-like symptoms. The results of porphyrin analysis are as follows: urine 5-aminolevulinic acid (ALA), positive; urine coproporphyrin III, increased; RBC zinc protoporphyrin (ZPP), increased. What laboratory test should the physician order to determine the exact diagnosis?

Blood lead

113)An individual is suspected of having some type of porphyria although he has no skin lesions. The qualitative screen demonstrates an elevated PBG and ALA in urine. Upon quantitation, the PBG was noted as being more increased than the ALA. Further quantitative tests indicated increased uroporphyrin and fecal porphyrin. The plasma fluorescence emission peak was at 624 to 628 nm. What is the likely diagnosis?

Variegate porphyria (VP)

114. Moderate elevations of what occur secondary to lead toxicity or iron-deficiency anemia?

ALA

115. The skin lesions observed in individuals with nonacute porphyria are caused by:

the excess presence of porphyrins in the skin that generate oxygen radicals.

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116. An important amino acid in the synthesis of ALA is: glycine.117. Porphyrin synthesis is regulated by modulation of what enzymes?

ALA-synthase (ALAS)

118. What cofactors is required for heme synthesis? Pyridoxal phosphate119. The enzyme that is an iron-sulfur protein located in the inner mitochondrial membrane that inserts ferrous iron into protoporphyrin to form heme is:

ferrochelatase.

120. The immediate precursor of the porphyrins is: porphobilinogen.121. A physician calls the laboratory stating that one of her patients is exhibiting what she suspects to be an acute porphyric attack. The patient is having acute abdominal pains and seems apathetic and distant. Initial laboratory analysis should include:

urinary PBG.

122. A physician calls the laboratory stating that one of her patients is exhibiting what she suspects to be an acute porphyric attack. The patient is having acute abdominal pains and seems apathetic and distant. If the urine test for PBG in the preceding question is strongly positive and remains elevated for 2 weeks or longer, what is the most likely disease process?

AIP

123. Erythrocyte protoporphyria (EPP): leads to progressive hepatic failure.

124. What is the name of the oxygen storage protein found in muscle that uses heme as its prosthetic group?

Myoglobin

125. An individual with jaundice reports to the emergency department with symptoms of an acute porphyric attack, including severe abdominal pain, pain in her thighs, vomiting, and muscle weakness. A hepatitis screen is negative and unconjugated bilirubin and urobilinogen are increased. Your laboratory receives a dark orange-colored urine sample for qualitative PBG analysis, results of which are difficult to interpret. When you contact the physician with this information, the physician informs you that this patient is an alcohol abuser and asks you to run a quantitative urine porphyrin analysis. Results of this analysis show an increased uroporphyrin and coproporphyrin III. Why was the PBG difficult to interpret?

There was interference from elevated urobilinogen in the urine sample.

126. When using DNA analysis to screen a new family to identify a genetic mutation that has caused porphyria, what must be examined?

All exons with promoters and flanking intron sequences around the mutation must be analyzed.

127. Protoporphyrin that contains iron is known as: heme.128. The heme precursor that is elevated in PCT is: uroporphyrin.129. When a drug concentration exceeds the available metabolic capacity of the body, what does the drug’s metabolism become dependent on?

The amount of metabolizing enzyme

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130. A hospital patient is receiving amikacin for her Enterobacter infection, which seems to be resistant to all other antibiotics. Her physician is somewhat unfamiliar with the antibiotic and wants to know what laboratory analyses can be performed to assess this antibiotic’s efficacy and risk of toxicity. You suggest:

both peak and trough amikacin concentration assessment.

131. What could account for drug toxicity following a prescribed dose?

Decreased renal elimination leading to increased free drug concentration

132. The fraction of drug absorbed into a physiological system that is based on the amount of drug given is referred to as:

bioavailability.

133. If a drug is acidic in nature, what proteins will it associate with primarily for transport and distribution?

Albumin

134. The therapeutic range of a drug is: the range of concentrations within which the drug is effective yet not toxic.

135. The period of time during which the concentration of a therapeutic drug decays by 50% is referred to as the drug’s:

half-life.

136. A hospitalized patient is being given gentamicin to treat a gram-negative bacterial infection. The patient’s physician contacts you regarding monitoring of this antibiotic because this patient is beginning to exhibit signs of hearing loss and renal failure. When you assess the patient’s 10-hour postinfusion trough antibiotic concentration, it is increased. You learn from the physician that he has been dosing the patient to keep the antibiotic concentration high, “at a steady state” he tells you. You state that:

with aminoglycoside antibiotics, trough concentrations must be allowed to decrease because of the postantibiotic effect.

137. The steady state of a drug is defined as the: point at which the body concentration of the drug is in equilibrium with the rate of dose administered and the rate of elimination.

138. A woman is treated for a seizure disorder with levetiracetam. She began experiencing dizziness and fatigue. Blood cell values indicated decreased RBC count and low hematocrit. Trough blood concentration of levetiracetam was assessed to be 15 µg/mL, although her dosing should have resulted in a trough therapeutic concentration of 3 µg/mL. She claimed that she was not taking antacids or any other medication. What is the likely cause of the elevated levetiracetam?

The patient might have an issue with her renal function, leading to decreased elimination of the drug.

139. What is a major active metabolite of procainamide that must be monitored along with the parent drug?

N-acetylprocainamide

140. What do both cyclosporine and tacrolimus inhibit? Calcineurin

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141. What immunosuppressant prodrugs inhibits inosine monophosphate dehydrogenase (IMPDH) to reduce the pool of intracellular guanine nucleotides and arrest T-cell proliferation?

Mycophenolate mofetil

142. The therapeutic drug used to treat all but absence seizures by prolonging inactivation of the synaptic sodium channel and reducing synaptic transmission is:

phenytoin.

143. What is occurring in phase I metabolism of a therapeutic drug?

Chemical modification such as hydrolysis

144. What therapeutic drugs is considered to be a selective serotonin reuptake inhibitor?

Fluoxetine

145. A class III antiarrhythmic drug that acts by blocking potassium channels and that is used to manage atrial fibrillation is:

amiodarone.

146. What therapeutic drugs is used in the management of acute lymphoblastic leukemia and inhibits DNA synthesis by decreasing methylation of pyrimidine nucleotides and their synthesis?

Methotrexate

147. What is not a good rationale for monitoring the blood concentration of a therapeutic drug?

To monitor drugs with a broad therapeutic range

148. Mycophenolate mofetil (MMF) is rapidly hydrolyzed by widely distributed esterases in blood and tissue to produce MPA. In regard to drug metabolism, this chemical reaction is referred to as:

a phase I reaction.

149. The method of monitoring therapeutic drug concentrations that is replacing HPLC-based methods and is now considered to be the best technology for analysis of biological specimens with high specificity and fewer interferences is:

liquid chromatography–mass spectrometry/mass spectrometry.

150. For a therapeutic drug that has a short half-life, for example levetiracetam, when is the appropriate time to collect a blood sample for therapeutic drug assessment?

Immediately before a dose of the drug is given

151. The name given to the group of enzymes that are particularly involved in phase I metabolism of drugs and that involve reduction/oxidation or hydrolysis is:

cytochromes P-450.

152. An individual who appears to be very inebriated is brought to a hospital emergency department by the police. Laboratory blood gas results indicate metabolic acidosis with an increased serum osmol gap, the presence of serum acetone, and many urine oxalate crystals. Which alcohol did this individual ingest?

Isopropanol

153. What is the major metabolite of acetaminophen that is formed in the liver?

Glucuronide

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154.) In a clinical laboratory without gas chromatography instrumentation, the common method of choice used to measure ethanol in serum or plasma is a(n):

enzymatic analysis using alcohol dehydrogenase and measurement of nicotinamide adenine dinucleotide (NADH) formation.

155. In the liver methanol is metabolized by _____ to form _____.

alcohol dehydrogenase; formaldehyde

156. ) Your toxicology testing facility tests urine samples. New screening tests for methamphetamine and amphetamine have been added to the drug profiles. Occasionally a positive methamphetamine immunoassay screening test is followed by a negative amphetamine confirmatory test result. What might cause this discrepancy?

Other chemically related compounds such as pseudoephedrine have been shown to produce positive results in amphetamine immunoassays.

157. In what specimen types is there a strong relationship between it and plasma free drug concentration, but the window of detection is short compared with that in a urine specimen?

Oral fluid

158.What enzymes is inhibited by organophosphate or carbamate compounds, such as those found in pesticides?

Acetylcholinesterase

159.A drug of abuse that stimulates the central nervous system by blocking dopamine reuptake and rapidly metabolizes to inactive benzoylecgonine and ecgonine methyl ester is:

cocaine

160.Respiratory alkalosis is a clinical feature of overdose ingestion of salicylate because:

salicylates induce hyperventilation.

161.An individual is found unconscious with two empty pill bottles nearby, one of aspirin and the other of phenobarbital. The best antidote for this type of double drug overdose would be:

forced alkaline diuresis.

162.The most common laboratory method for detection, discrimination, and quantitation of alcohols in biological specimens is:

flame ionization gas chromatography (GC).

163. In a chronic user of marijuana, the metabolite will remain in urine for what period of time?

Up to 73 days

164.A type of drug test that is used to rule out the presence of drugs or to suggest the presence of a particular drug group and that has been replaced by rapid immunoassay tests is the _____ test.

spot

165.The correct formula for determining anion gap is: [Na+] – [Cl- + HCO –]

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166.An 18-year-old man who had been found unresponsive and face down in his bed after spending the day working in his garage is brought to the hospital emergency department. He had not responded to naloxone administration given by the paramedics. His history reveals that he was despondent over the recent death of his father, with whom he enjoyed restoring antique automobiles. Laboratory results indicate negative serum acetone, elevated serum urea and creatinine, normal PO2, decreased bicarbonate, increased PCO2, and increased osmol gap (corrected for ethanol) and anion gap. Urinalysis indicated many oxalate crystals. Based on these laboratory results, what is the likely compound that has affected this individual?

Ethylene glycol

167. With the above patient, Based on these laboratory results and the likely compound that has affected this individual, what are the metabolizing enzyme and the metabolite(s) formed from the toxic compound?

Alcohol dehydrogenase; glycolic and oxalic acids

168. With the above patient, what is the best therapy? Fomepizole169. With the above patient, a second anion gap is

calculated and the value has increased from the initial value. Based on these laboratory results and the likely compound that has affected this individual, what type of acid-base imbalance is present?

Metabolic acidosis

170.What best explains the toxic effect of acetaminophen overdose?

The hepatic necrosis is caused by depletion of a substance in the liver andeventual accumulation of the oxidized metabolite.

171.Following a school field trip to the country, four teenage boys are admitted to the hospital emergency department with visual system impairment and severe abdominal pain. Laboratory evaluation reveals metabolic acidosis, increased anion gap and osmol gap, negative serum acetone, and no unusual urine sediments. Intoxication by what is most likely responsible?

Methanol

172.You receive a filled purple-top (EDTA-containing) tube with a request for a cyanide assay that requires a whole blood sample. You:

know that the tube you received is perfectly fine if well mixed and proceed to run the sample to check for evidence of cyanide.

173.The enzyme responsible for the metabolism of delta-9-tetrahydrocannabinol (THC) to its various metabolites is:

CYP2D6

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174.To recognize a poisoning pattern, groups of drugs with similar actions, symptoms, and clinical signs are examined. These common signs and symptoms are referred to as the:

toxidrome.

175.An example of a nonbenzodiazepine sedative-hypnotic that is used in drug-facilitated sexual assault that interacts with a subtype of the GABAA receptor complex is:

zolpidem.

176.Agents related to the anticholinergic toxidrome include all of the following except:

organophosphates.

177.A symphathomimetic drug that can be a drug of abuse but has legitimate pharmacologic use as a treatment for narcolepsy is:

amphetamine.

178.Because of its rapid turnaround time, the laboratory method of choice used to screen urine samples for their opiate content is:

immunoassay.

179.Cocaine is subject to recreational abuse because it: blocks dopamine reuptake at nerve synapses and prolongs the action of dopamine in the CNS, leading to feelings of euphoria.

180.Meconium is a difficult substance to analyze in a clinical laboratory for drug assessment because:

it is a difficult material to work with, and drug testing is far less standardized than for a urine specimen.

181.A positive urine immunoassay screening test for a drug of abuse must be confirmed by:

GC-MS.

182.The best antidote for overdose with heroin is: naloxone.183.Laboratory analysis of what enzyme activities is

performed to assess acute neurotoxicity from organophosphate or carbamate poisoning?

Acetylcholinesterase

184.An individual is brought to the hospital emergency department with nausea, vomiting, and an altered mental status. An empty bottle of nonprescription enteric-coated acetylsalicylic acid (aspirin) was found at her bedside by her husband 30 minutes earlier. Although all signs and symptoms point to salicylate overdose, laboratory analysis indicated no acid-base disorder and low salicylate concentration using a photometric procedure. What is the explanation of this discrepancy?

The enteric-coated pills delayed aspirin absorption and blood work was collected before the salicylate could reach maximum concentration.

185.The laboratory method of analysis that is accurate and precise for very low concentrations of carbon monoxide is:

gas chromatography.

186.The occurrence of cell membrane damage causing normal cells to be replaced with fibroblasts occurs in the heart because of a deficiency of what metals?

Selenium

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187. In blood collection for chromium or other trace metal analysis, what aspect of specimen collection is critical?

Using specially manufactured collection tubes with unique stoppers

188.What blood analyte does a toxic overdose of aluminum affect?

Parathyroid hormone

189.An individual is admitted to the hospital with markedly increased liver enzymes (transferases) and unusual behavioral changes noted by her family. A protein electrophoresis reveals decreased ceruloplasmin. What toxic metals might be implicated in this individual’s symptoms?

Copper

190.A byproduct of zinc and lead smelting, this metal is also used in the production of rechargeable batteries. Chronic exposure to this metal results in renal damage and breathing its fumes causes pulmonary congestion resembling chronic emphysema

Cadmium

191.What is a toxic metal that produces Mees’ lines upon overdose exposure by denaturing keratin in fingernails?

Arsenic

192.Lead produces a serious toxic effect when ingested because it:

does not allow for the incorporation of heme into the porphyrin molecule.

193.What is the specimen of choice for determining arsenic exposure in an individual and why?

Urine is the specimen of choice because arsenic is concentrated in and excreted predominantly by kidneys.

194.Both mercury and arsenic produce their symptoms of toxicity in a similar way. This includes:

binding to the sulfhydryl groups of protein causing loss of protein activity.

195.A four-member family of fish-loving vegetarians has become ill and visits their family practitioner. Their symptoms include stumbling (ataxia), visual field loss, and urinary difficulties. No Mees’ lines are observed. Being environmentally conscious, they have their home examined for toxic gases. All tests are negative. Based on their history and symptoms, what toxic metal might be to blame?

Mercury

196.A four-member family of vegetarians has become ill and visits their family practitioner. Their symptoms include stumbling (ataxia), visual field loss, and urinary difficulties. No Mees’ lines are observed. Based on their symptoms and knowledge of the correct metal involved, what is the best therapy?

British anti-Lewisite (BAL)

197.All of the following factors must be demonstrated before metal toxicity is considered a diagnosis except:

More than two organ systems must be affected.

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198.When reporting the results of a urine metal analysis, such as urine chromium, how are the results reported?

In concentration units of the metal of interest per gram of creatinine

199.Certain metals are essential for life at low concentrations and typically function as protein cofactors required for enzymatic reactions. These particular elements are located in which group(s) and row(s) of the periodic table?

Groups 6 through 12, row 4

200. Match the disorder with the diagnostic analyte measured in the laboratory.

A. Plasma/urine metanephrinesB. Urinary VMAC. MelatoninD. Urinary 5-HIAA

A. Tumor of adrenal medullary chromaffin cells

B. NeuroblastomaC. Pineal gland tumorD. Gastroenteropancreatic

endocrine tumor201. Match the correct vitamin to the disorder that

the vitamin deficiency would cause:A. ThiamineB. RetinolC. QuinoneD. Cobalamin

A. BeriberiB. Night blindnessC. Impaired blood coagulationD. Megaloblastic anemia

202. Match the trace or ultratrace elements with the clinical disorders associated with either deficiency or toxicity:A. ChromiumB. ManganeseC. CopperD. Selenium

A. Lung cancerB. Parkinson disease-like

symptomsC. Menkes diseaseD. Loss of immunocompetence

203. Match each drug with its major therapeutic use:A. ImipramineB. MethotrexateC. QuinidineD. Lamotrigine

A. AntidepressantB. AntimetabolicC. AntiarrhythmicD. Antiepileptic

204. Match each drug with its major mode of action:A. AmitriptylineB. ProcainamideC. PhenobarbitalD. Sirolimus

A. Tricyclic antidepressantB. AntiarrhythmicC. AntiepilepticD. Immunosuppressant

205. Match the compound with the antidote for overdose:A. N-acetylcysteineB. Activated charcoalC. AtropineD. Hydroxycobalamin

A. AcetaminophenB. Salicylic acidC. OrganophosphatesD. Cyanide

206. Match the compound with its metabolite:A. Glycolic acidB. MorphineC. Carboxylic acidD. Acetaldehyde

A. Ethylene glycolB. HeroinC. BarbiturateD. Ethanol

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207. Match the drug with its correct elimination half-life.A. DiazepamB. HeroinC. CocaineD. . Carboxyhemoglobin

A. 21 to 37 hoursB. 2 to 6 minutesC. 30 mins to 1.5 hoursD. 5 to 6 hours

208. Match the substance with the suggested antidote for its overdose.

A. Anticholinergic agentsB. Ethylene glycolC. MethemoglobinemiaD. Benzodiazepine

A. 232. PhysostigmineB. 233. EthanolC. 234. Methylene blueD. 235. Flumazenil

209. Match the toxicant with its specific effect.A. Pesticides (carbamates)B. Carbon monoxideC. MethamphetamineD. Ethanol

A. 236. Interferes with enzyme action

B. 237. Blocks oxygen binding to hemoglobin

C. 238. Central nervous system stimulant

D. 239. Central nervous system depressant

210. Name the metal that might alter the results of the below analytical issue.

a Reduced to a nontoxic form in biological specimens

b Blood specimens are not especially useful; urine is best

c Requires a lymphocyte proliferation test; serum or urine quantification is not useful

d To examine erythrocytes, EDTA-anticoagulated blood is specimen of choice

A. LeadB. BerylliumC. ArsenicD. Chromium

204.True or False: Whole blood specimens stored at 37° C will demonstrate a falsely increased potassium value because of red blood cell hemolysis.

False

205. True or False: Dopamine in the central nervous system functions as a neurotransmitter important for regulating an overall state of attention and vigilance.

False

206. True or False: In the analysis of plasma porphyrins, porphyrins at neutral pH fluoresce between 610 to 640 nm.

True

207. True or False: The long elimination half-life of marijuana that affects the duration of detection is due to the reentry of THC from tissue fat stores into the circulation

True

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