TestNormal ValuesAbnormal ColorInterfering Factors

Appearance and ColorNormal specimen should be clear/straw colored (pale yellow to amber b/c of pigment urochrome product of bilirubin metabolism)- Pathologic condition or ingestion of certain foods- Cloudy presence of WBCs, RBCs, bacteria- Red bleeding (dark red from kidney, bright red from bladder); eating beets- Dark yellow bilirubin or urobilinogen- Green pseudomonas infection- Brown eating rhubarb- Certain drugs can change urine color-Different medications(Table on p. 959)-Urine refrigerated longer than 1 hr (cloudy)-Certain foods-Darkens upon standing (oxidation of bilirubin)

TestIndicationsNormal Values

Abnormal IncreaseAbnormal DecreaseInterfering Factors

Specific Gravity Measure kidneys ability to concentrate urine (remove wastes) Weight of urine is compared to the weight of distilled water (1.000) Value affected by amount of solutes and volume, hydration statusAdult: 1.005 1.030 (usually, 1.010 1.025)Elderly: values decrease with ageNewborn: 1.001 1.020(qualitative test)- high concentration = high specific gravity- Diabetes Mellitus- Excessive water loss; dehydration- Increased secretion of antidiuretic hormone

- low concentration = low specific gravity - Diabetes Insipidus - Chronic Renal Diseases diminished concentrating ability-Recent use of radiographic dyes SG-Cold temperatures SG-Drugs may SG (dextran, mannitol, sucrose)

Urine Osmolality Evaluate fluid and electrolyte abnormalities Determination of kidneys concentration capabilities Investigate antidiuretic hormone abnormalites50 1200 mOsm/kg random(quantitative test)- high concentration = high specific gravity- Diabetes Mellitus- Excessive water loss; dehydration- Increased secretion of antidiuretic hormone

- low concentration = low specific gravity - Diabetes Insipidus - Chronic Renal Diseases diminished concentrating abilityDrugs such as aminosalicylic acid, barbiturates, chloral hydrate, chlorpropamide, ethyl alcohol, griseofulvin, morphine, oral contraceptives, procaine, sulfonamides

TestIndicationsNormal ValuesAbnormal IncreaseAbnormal Decrease

Interfering Factors

pH acid/base Tubules ability to maintain H+ in plasma and extracellular fluid Tubule secretes hydrogen as sodium is reabsorbed in proximal convoluted tubule and distal convoluted tubule4.6 8.0(average 6.0)- Acidemia- Diets high in cranberries, metabolic or respiratory acidosis- Associated with xanthine, cysteine, uric acid, and calcium oxalate stones - Metabolic or respiratory acidosis, starvation, dehydration- Bacteria- UTIs- alkalemia- Associated with calcium carbonate, calcium phosphate, and magnesium phosphate stones.- Renal tubular acidosis-Becomes alkalne on standing (urea-splitting bacteria produce ammonia)-Uncovered specimen become alkaline (CO2 vaporizes from urine)-Dietary factors-Certain drugs pH (acetazolamide, bicarbonate antacids) and pH (ammonium chloride, chlorothiazide)

Protein Indicator of kidney function Normally protein not in urine spaces in glomerular membrane too small to allow passagenegative0 8 mg/dL- Proteinuria- Preeclampsia HTN, edema- Eclampsia preeclampsia with seizures- Complications of diabetes decreased renal blood flow- Glomerulonephritis glomerular membrane damage- Amyloidosis- Multiple myeloman/a-Severe emotional stress, excessive exercise, and cold baths-Radiopaque contrast media administered 3 days prior (false-positive)-Diet high in protein-Concentrated urine-Hemoglobin-Drugs protein (penicillin, vancomycin, griseofulvin, methicillin, polymixin B, sulfonamides)

Test

Indications

Normal Values

Abnormal Increase

Abnormal Decrease

Interfering Factors

Blood-Any disruptions in the blood-urine barrier will cause RBCs to enter the urine.Negative (RBCs 2)- Hematuria- Cystitis bladder, lower UTI- Glomerulonephritis glomerular membrane damage- Cancer- Tumors, trauma, stones, infection that involve the mucous membranes in the collecting systemn/a-Strenuous physical exercise RBC casts-Traumatic urethral catherization may cause RBCs in urine-Overaggressive anticoagulation therapy or bleeding disorders tend to cause RBCs in urine without concomitant disease

Glucose- Indicates possible diabetes - Direct measure of glucose in the urineFresh specimen: Negative(positive results reported as 100 2000 mg/dL)24-hour specimen: 50-300 mg/24 hr or 0.3 1.7 mmol/day

- Familial hyperglucagonemia- Diabetes Mellitus- Chronic renal failure- Severe stress- Acromegaly

n/a

-Radioactive scan within previous 48 hrs and glucagon measured by RIA. Administration of radionuclides-Prolonged fasting, stress, or moderate to intense exercise-Drugs (amino acids, gastrin, insulin, glucocorticoids)

Ketones- Byproduct of fatty acid catabolism- Used as energy source when glucose cannot be utilized-provide energy source when glucose cannot be transferred into the cell due to insulin insufficiencyNegative(positive reported as 1+ to 4+)- Poorly controlled diabetes, hyperglycemia- Diabetic ketoacidosis- Alcoholic ketoacidosis- Starvation- High protein Diet- Isopropanol ingestion- Acute febrile illnessesn/a- Special diet (carb-free, high-protein, high-fat) may cause ketonuria- Drugs cause (isoniazid, isopropanol, paraldehyde)

TestIndicationsNormal ValuesAbnormal Increase

Abnormal Decrease

Interfering Factors

Bilirubin- Major constituent of bile- Breakdown of hemoglobin- Conjugated in liver and excreted in bile, which is metabolized in small intestine by bacteria to urobilinogen- Unconjugated fat soluble (difficult to excrete)- Conjugated water soluble (easily excreted) can go thru kidneysNone/negative- Disease affecting bilirubin metabolism or excretion after conjugation - Obstruction of bile duct; gallstones- Certain drugs oral contraceptives- Conjugated hyperbilirubin- Turns urine dark yellow or orangen/a-Not stable when exposed to light

Urobilinogen- Bilirubin transformed by action of bacteria (in intestines)- Portion of urobilinogen absorbed and carried to liver and excreted in bile and urine0.01 -1 Ehrlich unit/mL(Results usually normal some always in urine)Abnormal results reported numerically if > 0.2mg/dL- Overproduction (hemolytic anemia)- If you dont see urobilinogen, bilirubin did not get changed into urobilinogen in the small intestines- pH levels; alkaline levels; acidic levels- Phenazopyridine turns urine orange (false impression of jaundice)- Cholestatic drugs levels- Antibiotics reduce intestinal flora, levels

Leukocyte Esterase- Detect leukocytes in urinenegative- Positive tests indicates UTI- MOST reliable rest for UTI (90% accurate)n/a- False +: contaminated by vaginal secretions that contain WBCs- False -: contain high levels of protein or ascorbic acid

TestIndicationsNormal ValuesAbnormal IncreaseAbnormal DecreaseInterfering Factors

Nitrites- Screening test for identification of UTI- Bacteria (gram neg. only) produce enzyme reductase, can reduce urinary nitrates to nitrites. None- Positive test indicates UTI, with positive leukocyte esterasen/an/a

Crystals- Microscopic examination- Indicate that renal stone formation is imminent, if not already present- Type of crystals varies with disease and pH of urineNone- Crystals in acidic urine Uric acid crystals (gout) Calcium oxalate (envelopes compose most kidney stones)- Crystals in alkaline urine Calcium phosphate (little clinical significance) Triple phosphate (coffin lids a/w stones, chronic cystitis)- Phosphate and calcium oxalate crystals occur with parathyroid abnormalities or malabsorption states- Some crystals observed when SG n/a- Radiographic contrast media may cause precipitation of urinary crystals

Test

Indications

Normal Values

Abnormal Increase

Abnormal Decrease

Interfering Factors

Casts- Casts formed only in distal convoluted tubule or collecting duct- Formation favored by decreased urine flow, increased sodium concentration and acidic pH- Associated with some degree of proteinuria and stasis within renal tubules- Exact picture of tubule it came fromNone- Hyaline Casts Made of protein Composed primarily of mucoprotein called Tamm-Horsfall protein secreted by tubule cells Can be seen in normal patients, especially after strenuous exercise, dehydration- Cellular Casts Made up of cells When cellular casts remain in nephron long time, may degenerate into coarsely granular casts, then finely granular casts and ultimately broad waxy castsn/an/a

Epithelial cells are found during microscopic examination and are found in patients who have contamination (contaminated sample) Cellular Casts Granular Casts Result from degeneration of cellular material into granular particles within WBC or epithelial cell cast Found after exercise and in renal disease Fatty Casts Fat within epithelial cell casts becomes incorporated with protein into casts of coalesce to large droplets called oval fat bodies Hallmark of nephrotic syndrome Waxy Casts May be cell casts or hyaline casts Occur when flow through tubule diminished and granular casts degenerate A/w chronic renal diseases and chronic renal failure, diabetic nephropathy, malignant HTN Epithelial Cell Casts May be squamous of renal tubule May be shed into urine from bladder as result of tumor, infection, polyps Squamous epithelial cell casts can be normal Renal tubular cell casts indicate glomerulonephritis White Blood Cell Casts Found in infections, mostly pyelonephritis, inflammatory nephritis (lupus) Red Blood Cell Casts Found with disruption of blood/urine barrier at any level of tract, usually bladder, ureteral, urethral diseases Casts indicate membrane damage glomerulonephritis