General Principles of Lab Testing

Question	Answer
3 Distinct layers in PCV tube	The plasma column at the top The packed erythrocytes at the bottom The small, middle white band known as the buffy coat
Icterus	Excessively yellow pigmentation of the plasma that suggests hyperbilrubinemia
Lipemia	White, opaque coloration of the plasma column because of the presence of chylomicrons. Most commonly is associated with the postprandial collection of blood, also disorders involving lipid metabolism.
Hemolysis	Red discoloration of the plasma column, which results from artifactual lysis of red cells induced during collection of blood.
Total Leukocyte Count	the concentration of nucleated cells
Blood smear	to determine the concentrations of individual leukocyte types and evaluating abnormalities of leukocytes, erythrocytes, and platelets.
Within the counting area you will obtain the differential leukocyte count by classifying a minimum of ___ consecutively encountered cells.	100
6 categories of normal cells	Neutrophil Band Neutrophil Lymphocyte Monocyte Eosinophil Basophil
Conversion of % counts to absolute concentrations	Total WBC count = 10,000/uL Differential WBC count - Ex: Neutrophils 60% = 6000 Absolute Numbers Lymphocytes 30% = 3000 Monocytes 5% = 500
Platelet adequacy	Minimum of 8-12 platelets/oil immersion high power (1000x) field is considered adequate - if platelets appear decreased, search for platelet clumping on low power setting at feathered edge
Hemoglobin Concentration	the index of the red cell mass per unit volume of blood in the patient
Mean cell hemoglobin	calculated from the hemoglobin concentration and erythrocyte concentration
Mean cell hemoglobin concentration	MCHC calculated from the hemoglobin concentration and the hematocrit Calculation: HGB/PCV% x 100 = MCHC Example: 10/30% x 100 = 33.3 g/dL
MCHC for all mammalian species	ranges from 33-38 g/dL camel family is higher 41-45 g/dL
Severe hemolysis in the sample is a common cause of an increased MCHC	True
Erythrocyte agglutination, as may occur in immune-mediated hemolytic anemia, may result in a false high MCHC	True
Erythrocyte concentration	measured directly by counting the erythrocyte particles in an isotonic dilution of blood
How is the hematocrit (HCT) calculated?	using the erythrocyte concentration (RBC) and the mean cell volume (MCV) MCVxRBC/10 = HCT MCV 70 x 7.00 RBC/10 = HCT 49%
Cats are an exception in that their platelets are approx twice the volume of those in other domestic species	True
The reticulocyte concentration is very useful in the evaluation of _______	Anemia
Absolute Reticulocyte Concentration	Calculated: RBC/uL x % Reticulocyte = Reticulocytes/uL
Reticulocyte concentration is...	most useful in dogs and cats and sometimes cows. Horses do not release reticulocytes Reticulocyte Concentration to be expected when the HCT is normal: Dogs and Cats = 0-60,000 cells/uL Cows = 0 cells/uL
Guidelines for the interpretation of reticulocyte concentrations with respect to the type of anemia present:	Nonregenerative anemia to very poor regeneration = 0-10,000 cells/uL Nonregenerative to poorly regenerative anemia = 10,000-60,000 cells/uL Regenerative anemia with mild to moderate output = 60,000-200,000 cells/uL Maximal regeneration = 200,000-500,000 cells/uL
In dogs, reticulocyte maturation occurs in...	24-48 hours
Maturation involves what	a continuum of progressive loss of the visible organelles
Complete blood count includes: a) Direct Measurements	PCV Hemoglobin concentration Red Cell Concentration (RBC) Mean Cell Volume (MCV) White Cell Concentration Plasma proteins Platelet concentration Mean Platelet Volume (MPV)
Complete blood count includes: b) Microscopic procedures	Differential white cell count Red cell morphology Platelet morphology and assessment of adequacy Microscopic reticulocyte enumeration in patients with anemia
Complete blood count includes: c) Calculations	Hematocrit Erythrocyte indices (MCHC, MCH, RDW) Absolute white blood cell differential values Absolute reticulocyte count
The Coombs Test	or antiglobulin test used as an aid in establishing the diagnosis of immune-mediated hemolytic anemia by detecting species-species immunoglobulin that is absorbed or attached to the surface of erythrocytes
False-negative reactions are a common problem with the Coombs test	True
Spectrophotometry	should be applied when the instrument being used has the ability to produce light of a variety of wavelengths through some type of light-fractionating device such as filters, prisms, or diffraction gratings
Absorbance Spectrophotometry	technique in which concentrations of substances are determined by directing a beam of light through a solution containing substance to be detected and then measuring the amount of light that either of these absorb
Monochromator	optical device between the light source and the measuring cuvette
Cuvettes are also known as what	absorption cells
Glucose is metabolized at a rate of ____ per hour if left in contact with cellular element	10%
The most common procedure for making a quality blood film is the wedge technique and uses two glass slides	True
BUN stands for what? BUN tests what?	Blood Urea Nitrogen Kidneys
Antibodies or immunoglobulins are what?	proteins produced by differentiated B-lymphocytes.
5 classes of antibodies	Immunoglobulin A (IgA) Immunoglobulin D (IgD) Immunoglobulin E (IgE) Immunoglobulin G (IgG) Immunoglobulin M (IgM)
Primary function of erythroyctes is	to transport hemoglobin, which carries oxygen to the tissues
Polychromatophilic cells are	young erythrocytes that have been released early
Poikilocytes	abnormally shaped erythrocytes
______ is classified as either regenerative or non regenerative	anemia
Most nonregenerative anemias are	normocytic

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General Principles of Lab Testing

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	Created by Nicole Roberts over 9 years ago