Diagnostic Laboratory Diagnostic Laboratory Blood TestsBlood Tests

Complete Blood Count and Complete Blood Count and

Blood Chemistry ProfilesBlood Chemistry Profiles

Blood CountsBlood Counts

Complete Blood CountComplete Blood Count

Evaluations of cellular parametersEvaluations of cellular parameters Types of cellsTypes of cells Numbers of cellsNumbers of cells Size and volume of cellsSize and volume of cells

CBCCBC

Provides a “snap shot “ of the Provides a “snap shot “ of the hematopoietic system at a specific hematopoietic system at a specific point in time.point in time.

CBC ComponentsCBC Components

White blood cell White blood cell countcount

Differential countDifferential count Red blood cell Red blood cell

countcount HematocritHematocrit HemoglobinHemoglobin

Mean corpuscular Mean corpuscular volumevolume

Mean corpuscular Mean corpuscular hemoglobinhemoglobin

Mean corpuscular Mean corpuscular hemoglobin hemoglobin concentrationconcentration

White Blood Count (WBC)White Blood Count (WBC)

White blood cells (leukocytes) are White blood cells (leukocytes) are the disease fighting cells of the the disease fighting cells of the immune system.immune system.

Only about 1% of blood cells are Only about 1% of blood cells are WBCsWBCs

Large numbers of WBCs can be Large numbers of WBCs can be produced rapidly if needed produced rapidly if needed

White Blood Count (WBC)White Blood Count (WBC)

The WBC tells the total number of The WBC tells the total number of white cells present in a specified white cells present in a specified volume of bloodvolume of blood

Different disease states affect the Different disease states affect the WBC in different waysWBC in different ways

WBC MethodsWBC Methods

HemocytometerHemocytometer

Automated cell countersAutomated cell counters

Quantitative Buffy Coat AnalysisQuantitative Buffy Coat Analysis

Manual HemocytometerManual Hemocytometer

Manual counting is the oldest and Manual counting is the oldest and most time consuming method of most time consuming method of determining cell counts determining cell counts

Special slides and diluting fluids are Special slides and diluting fluids are requiredrequired

Method can be used for counting Method can be used for counting cells in other body fluids and cells in other body fluids and effusionseffusions

Advantages of Manual Advantages of Manual Counts Counts

Manual counting is the least Manual counting is the least expensive in terms of equipment and expensive in terms of equipment and suppliessupplies

Can be performed in a mobile clinic Can be performed in a mobile clinic

Limitations of Manual Limitations of Manual CountsCounts

Time consuming (staff expense)Time consuming (staff expense)

Inherent error (20%), even with Inherent error (20%), even with skilled staffskilled staff

Requires well trained and meticulous Requires well trained and meticulous personnelpersonnel

Manual Counts Manual Counts

WBC count is the most frequently WBC count is the most frequently performed hemocytometer countperformed hemocytometer count

RBC counts are very inaccurateRBC counts are very inaccurate Meticulous attention to detail is Meticulous attention to detail is

necessary to achieve consistent cell necessary to achieve consistent cell count results when using manual count results when using manual methodsmethods

HemocytometerHemocytometer

Automated Cell CounterAutomated Cell Counter

Several types now available for use Several types now available for use in vet settingsin vet settings

All types are more accurate than All types are more accurate than manual methodsmanual methods

Results are obtained rapidlyResults are obtained rapidly

TypesTypes

Semi-automated requires some Semi-automated requires some sample preparation by technical staffsample preparation by technical staff

Fully automated performs all steps Fully automated performs all steps itselfitself

Automated Cell CounterAutomated Cell Counter

Impedance methodsImpedance methods

All make use of Coulter principleAll make use of Coulter principle

AdvantagesAdvantages

Faster and more effective use of staff Faster and more effective use of staff timetime

Newer models store calibrations for Newer models store calibrations for multiple speciesmultiple species

Can perform most of components of Can perform most of components of a complete blood counta complete blood count

LimitationsLimitations

Cannot perform differential countsCannot perform differential counts Cannot recognize reticulocytesCannot recognize reticulocytes Cannot reliably differentiate between Cannot reliably differentiate between

WBCs and nucleated RBCsWBCs and nucleated RBCs Several artifacts can create false Several artifacts can create false

countscounts

Quantitative Buffy Coat Quantitative Buffy Coat AnalysisAnalysis

QBC is based on differential centrifugationQBC is based on differential centrifugation Uses special tubes that contain a float that Uses special tubes that contain a float that

has the same density as the buffy coathas the same density as the buffy coat When spun under high speed, the buffy When spun under high speed, the buffy

coat components are separated out by coat components are separated out by density (weight)density (weight)

Automated reader scans buffy coat and Automated reader scans buffy coat and records percentages of aggregates records percentages of aggregates

Advantages of QBC AnalysisAdvantages of QBC Analysis

Efficient and economical methodEfficient and economical method Simple to operateSimple to operate Good for rapid screening in office Good for rapid screening in office The system flags abnormal or The system flags abnormal or

unexpected resultsunexpected results

Limitations of QBC AnalysisLimitations of QBC Analysis

Cannot produce a complete Cannot produce a complete differential countdifferential count

Cannot distinguish between Cannot distinguish between lymphocytes and monocyteslymphocytes and monocytes

Does not distinguish between segs Does not distinguish between segs and bandsand bands

Increased WBCsIncreased WBCs

Bacterial infections generally Bacterial infections generally increase the numbers of white cells increase the numbers of white cells presentpresent

PyometraPyometra Bacterial pneumoniaBacterial pneumonia PeritonitisPeritonitis

Decreased WBCsDecreased WBCs

Viral infections tend to reduce Viral infections tend to reduce numbers of WBCsnumbers of WBCs

ParvovirusParvovirus Canine DistemperCanine Distemper Feline panleukopeniaFeline panleukopenia

Decreased WBCs Decreased WBCs

Immune system inadequacyImmune system inadequacy Bone marrow diseaseBone marrow disease Overwhelming bacterial infectionOverwhelming bacterial infection

Differential CountsDifferential Counts

Important in order to interpret the Important in order to interpret the WBC resultsWBC results

Gives much of the information Gives much of the information needed to interpret WBCsneeded to interpret WBCs

To date, no machine is able to To date, no machine is able to perform this task adequately and perform this task adequately and completelycompletely

Red Blood Cell CountRed Blood Cell Count

The measurement of RBCs is a way The measurement of RBCs is a way of evaluating the blood’s ability to of evaluating the blood’s ability to deliver oxygen to tissues and to deliver oxygen to tissues and to carry carbon dioxide awaycarry carbon dioxide away

Changes in the morphology of RBCs Changes in the morphology of RBCs can give information about bone can give information about bone marrow functionmarrow function

Some infectious agents or parasites Some infectious agents or parasites may be seen on the RBC surfacemay be seen on the RBC surface

HematocritHematocrit

Measures the percentage of RBCs in Measures the percentage of RBCs in the total bloodthe total blood

Can give information about the Can give information about the animal’s state of hydrationanimal’s state of hydration

May show evidence of RBC May show evidence of RBC destruction in the spleen destruction in the spleen

HemoglobinHemoglobin

Hemoglobin is the oxygen carrying Hemoglobin is the oxygen carrying protein in the RBCprotein in the RBC

Low levels of Hgb indicate genetic Low levels of Hgb indicate genetic problems, inadequate iron, problems, inadequate iron, inadequate B vitaminsinadequate B vitamins

High levels of Hgb may indicate High levels of Hgb may indicate abnormalities such as high iron abnormalities such as high iron intake, a toxin, or internal organ intake, a toxin, or internal organ malfunctionmalfunction

Mean Corpuscular VolumeMean Corpuscular Volume

MCVMCV Measures the size of the RBCsMeasures the size of the RBCs

Mean Corpuscular Mean Corpuscular HemoglobinHemoglobin

MCHMCH Reflects the average weight of the Reflects the average weight of the

hemoglobin in the RBCshemoglobin in the RBCs

Mean Corpuscular Hemoglobin Mean Corpuscular Hemoglobin concentrationconcentration

MCHCMCHC Measures the amount of hemoglobin Measures the amount of hemoglobin

in a given volume of packed red cellsin a given volume of packed red cells

Blood ChemistryBlood Chemistry

Blood Chemistry Values Blood Chemistry Values

Blood chemistry panels measure a Blood chemistry panels measure a variety of substances dissolved in the variety of substances dissolved in the plasma of bloodplasma of blood

Nutrients Nutrients Carrying agentsCarrying agents CatalystsCatalysts Waste matter Waste matter

Blood ChemistryBlood Chemistry

Substances are present in minute Substances are present in minute amountsamounts

Each substance contributes to the Each substance contributes to the overall health of the patientoverall health of the patient

Increases or decreases of chemicals Increases or decreases of chemicals can be good indicators of the patient’s can be good indicators of the patient’s conditioncondition

Can give valuable aid in making a Can give valuable aid in making a diagnosisdiagnosis

Aspartate AminotransferaseAspartate Aminotransferase

ASTAST Formerly called serum glutamic Formerly called serum glutamic

oxaloacetic transaminase (SGOT)oxaloacetic transaminase (SGOT) EnzymeEnzyme Levels increase with liver or severe Levels increase with liver or severe

muscle injurymuscle injury

Alanine AminotransferaseAlanine Aminotransferase

ALTALT Formerly known as serum glutamic Formerly known as serum glutamic

pyruvate transaminasepyruvate transaminase EnzymeEnzyme Levels increase in general liver injury Levels increase in general liver injury

Total BilirubinTotal Bilirubin

T BiliT Bili Measures the total amount of all Measures the total amount of all

bilirubin in the serumbilirubin in the serum Bilirubin is a pigment released in the Bilirubin is a pigment released in the

destruction of RBCsdestruction of RBCs Increased levels: Increased levels:

Intravascular hemolysisIntravascular hemolysis Primary liver or bile duct diseasePrimary liver or bile duct disease

Direct BilirubinDirect Bilirubin

D BiliD Bili Conjugated bilirubinConjugated bilirubin Bilirubin that has been combined Bilirubin that has been combined

with other compounds by the liverwith other compounds by the liver Increases levels often associated Increases levels often associated

with primary liver diseasewith primary liver disease

Indirect BilirubinIndirect Bilirubin

I BiliI Bili Unconjugated bilirubinUnconjugated bilirubin Bilirubin that has not yet been Bilirubin that has not yet been

combined with other substancescombined with other substances Increased levels usually associated Increased levels usually associated

with abnormal hemolysiswith abnormal hemolysis

Alkaline PhosphataseAlkaline Phosphatase

Alk PhosAlk Phos EnzymeEnzyme Related to bone, liver, bile duct Related to bone, liver, bile duct

systemsystem Increased levels:Increased levels:

Young, growing animalsYoung, growing animals Bone diseaseBone disease Liver diseaseLiver disease Bile duct blockageBile duct blockage Steroids and anticonvulsantsSteroids and anticonvulsants

Total ProteinTotal Protein

T Prot or TPT Prot or TP Measure both albumin and globulinMeasure both albumin and globulin Gives very general informationGives very general information Further division of proteins needed Further division of proteins needed

for meaningful interpretationfor meaningful interpretation

AlbuminAlbumin

ALBALB Major plasma Major plasma

proteinprotein Transports Transports

substances substances throughout bodythroughout body

Increases:Increases: DehydrationDehydration

Decreases:Decreases: Reduced production Reduced production

by liverby liver MalnutritionMalnutrition Chronic liver diseaseChronic liver disease Kidney diseaseKidney disease Tissue fluid loss from Tissue fluid loss from

wounds, burnswounds, burns

GlobulinGlobulin

GLOBGLOB Blood proteinBlood protein AntibodiesAntibodies Indicator of immune function Indicator of immune function

CholesterolCholesterol

CholChol Increases due toIncreases due to

Liver diseaseLiver disease DietDiet Thyroid diseaseThyroid disease Genetic abnormalities Genetic abnormalities

Blood Urea NitrogenBlood Urea Nitrogen

BUNBUN Associated with kidney functionAssociated with kidney function Levels increase with:Levels increase with:

Dehydration Dehydration High dietary proteinHigh dietary protein Small Bowel hemorrhageSmall Bowel hemorrhage Kidney diseaseKidney disease

CreatinineCreatinine

CreatCreat Breakdown product of skeletal Breakdown product of skeletal

muscle metabolismmuscle metabolism– Creatinine is filtered out by the kidneysCreatinine is filtered out by the kidneys– Used with BUN to determine kidney Used with BUN to determine kidney

functionfunction Not influenced by diet or GI bleedingNot influenced by diet or GI bleeding

PhosphorusPhosphorus

PhosPhos MineralMineral Levels are regulated by the kidneysLevels are regulated by the kidneys Linked with calcium , vitamin D, Linked with calcium , vitamin D,

parathormoneparathormone Increased in young, growing animalsIncreased in young, growing animals Increases occur with aging kidneys Increases occur with aging kidneys

and kidney failureand kidney failure

CalciumCalcium

Ca+Ca+ MineralMineral Important for skeletal strengthImportant for skeletal strength Needed for nervous system functionNeeded for nervous system function Regulated by parathyroid glandsRegulated by parathyroid glands Linked to Vit D, calcitonin, and others Linked to Vit D, calcitonin, and others

GlucoseGlucose

GlucGluc Essential source of energy for all Essential source of energy for all

cellscells Reacts to:Reacts to:

Insulin levelsInsulin levels Diet Diet GlucagonGlucagon Liver functionLiver function

Glucose increasesGlucose increases

HyperglycemiaHyperglycemia After eatingAfter eating StressStress ExerciseExercise Acute pancreatitisAcute pancreatitis Some drugsSome drugs

Glucose decreasesGlucose decreases

HypoglycemiaHypoglycemia MalnutritionMalnutrition ParasitismParasitism Increased insulinIncreased insulin

Administration of overdoseAdministration of overdose insulin producing tumor insulin producing tumor

AmylaseAmylase

Pancreatic enzymePancreatic enzyme Levels increase in Levels increase in

Acute pancreatitisAcute pancreatitis Kidney diseaseKidney disease

LipaseLipase

Pancreatic enzymePancreatic enzyme Levels increase in Levels increase in

Acute pancreatitisAcute pancreatitis Kidney diseaseKidney disease

SodiumSodium

Na+Na+ Major blood electrolyteMajor blood electrolyte Filtered by renal glomerulus, Filtered by renal glomerulus,

reabsorbed by renal tubules reabsorbed by renal tubules

SodiumSodium

Increased levels:Increased levels:– DehydrationDehydration– Increased salt Increased salt

intakeintake– Diabetes insipidusDiabetes insipidus– Kidney failureKidney failure

Decreased levels:Decreased levels:– Vomiting and Vomiting and

Diarrhea (can lead Diarrhea (can lead to metabolic to metabolic acidosis)acidosis)

– CHFCHF– Adrenal malfunction Adrenal malfunction

(Addison’s disease)(Addison’s disease)– Diabetes mellitusDiabetes mellitus

ChlorideChloride

CHLCHL An electrolyte that balances sodium An electrolyte that balances sodium

and potassium and potassium Increased levels indicate changes in Increased levels indicate changes in

overall electrolyte balance overall electrolyte balance

PotassiumPotassium

K+K+ Levels linked to Na+ Levels linked to Na+ Controlled by hormone aldosteroneControlled by hormone aldosterone

PotassiumPotassium

HyperkalemiaHyperkalemia Increases:Increases:

– Very seriousVery serious– Kidney failureKidney failure– Adrenal malfunctionAdrenal malfunction

HypoklalemiaHypoklalemia Decreases:Decreases:

– Decreased intakeDecreased intake– Excessive lossExcessive loss– Vomiting, diarrheaVomiting, diarrhea– Kidney diseaseKidney disease

Creatine KinaseCreatine Kinase

CKCK Formerly called creatine phosphokinase, or Formerly called creatine phosphokinase, or

CPKCPK

Associated with skeletal muscle or Associated with skeletal muscle or heart muscle damageheart muscle damage

Increases with:Increases with: MyositisMyositis TraumaTrauma Heart damageHeart damage

Uric AcidUric Acid

Blood uric acid reflects the end Blood uric acid reflects the end product of purine metabolismproduct of purine metabolism

Increases in:Increases in: General liver diseaseGeneral liver disease Genetic abnormalities in metabolism Genetic abnormalities in metabolism

(Dalmatians)(Dalmatians)

T3T3

TriiodothyronineTriiodothyronine Three iodine atoms attached to Three iodine atoms attached to

thyroxinethyroxine Thyroid hormoneThyroid hormone Regulates metabolism of all body Regulates metabolism of all body

cellscells

T3T3

IncreaseIncrease– Hyperthyroidism Hyperthyroidism

due to increased due to increased thyroid gland thyroid gland activityactivity

– TumorsTumors– Rare in dogsRare in dogs– Common in catsCommon in cats

DecreaseDecrease– In cases of reduced In cases of reduced

thyroid function thyroid function – In any generalized In any generalized

illnessillness– Very low if animal is Very low if animal is

gravely illgravely ill

T4T4

Tetraiodothyronine (4 iodine Tetraiodothyronine (4 iodine molecules)molecules)

Converted to T3 by the liverConverted to T3 by the liver Free T4 (FT4) less than 0.1 percent of Free T4 (FT4) less than 0.1 percent of

all T4, not bound to protein all T4, not bound to protein When measured accurately, most predictive When measured accurately, most predictive

of true thyroxine concentrationsof true thyroxine concentrations

T4T4

IncreaseIncrease– TumorsTumors– Thyroid gland Thyroid gland

hyperplasiahyperplasia

DecreaseDecrease– Reduced thyroid Reduced thyroid

gland function gland function