Heme Lab Final Review Complete

Indicates primary hemostasis issues like dysfunctional platelets or decreased platelet count.

Ivy
Duke

Most common bleeding time method using a blood pressure cuff.

less invasive bleeding time method without a blood pressure cuff.

Counting platelets in multiple fields and calculating the average number per field.

Count plts in one HP.
Move to another field and count.
5-10 diff fields need to be counted.
Calculate avg number of plts per field.
Multiple your avg by 17,000

Microcytes and schistocytes may be miscounted as platelets

Platelet clumps or large platelets can be miscounted as white or red blood cells.

make a thicker, shorter smear.

Make thinner, longer smear

too thick film
prolonged staining inadequate washing
high pH

Insufficient staining time
Prolonged washing time
Too low pH of stain or buffer

Citrated plasma (light blue top).

Tissue factor and calcium.

Phospholipid-rich preparation
Activator
Calcium chloride.

Turbidimetric, chromogenic, and immunologic.

As clot formation takes place, light transmission decreases

Analyte acts directly on specific chromogenic substrate (Protein C)

analyte of interest reacts under optimized test conditions.
Measures residual enzyme activity then measured using spec synthetic substrate conjugated with chromophore (e.g. heparin, antithrombin).

Immunological measures Ag-Ab immune complexes.

Standardizes results for patients on Coumadin

Warfarin/Coumadin use.

clot will not be dissolved after 24 hours

determines if pt sample is factor XIII deficient by placing clot in 5m urea

clot will dissolve in <24 hours

Cross-linked D fragments; increased D-dimer indicates cross-linked fibrin breakdown.

fibrinogen and fibrin degradation products

blood-clotting problems.

Stabilized fibrin clot is degraded (support Dx of DIC)

PT

VII

XII, XI, IX, VIII

X, V, II, I

Erythrocyte Sedimentation Rate

how fast the RBCs settle down the tube from plasma.

Rheumatoid arthritis, malignancy, multiple myeloma, bacterial infection, inflammatory disease

anemias, pregnancy, hyperfibrinogenemia states, increase in Igs, poikilocytosis

Manual hgb determination method using color intensity.

Erythrocytes are lysed by a stomatolytic agent in the presence of surfactant.

hgb released into solution.

hgb oxidized by methemoglobin by ferricyanide.

Methemoglobin is converted to stable cyanmethemoglobin by addition of KCN.

abs measured.
color intensity proportional to hgb conc.

WBC count = [WBC counted (N)/Volume (V)] X dilution factor

Volume = 4 X (1 X 1 X .1) = 0.4 mm^3

WBC Count = (N/V) X dilution factor = (N/0.4) X 20

RBC count= [RBC counted (N)/volume (V)] X dilution factor

Volume= 5 X (0.2 X 0.2 X 0.1) =0.02 mm3

RBC count = (N/V) X dilution factor = (N/0.02) X 200

Volume, Conductivity, Scatter

VCS utilizes the Coulter Principle of direct current (DC) impedance to physically measure the volume. This method accurately sizes all cell types regardless of their orientation in the light path.

Alternating current short circuits the bipolar lipid layer of the membrane. Highfrequency electromagnetic probe determines the conductivity. Collects internal structure information, including chemical composition and nuclear volume.

Laser beam technology is used to scatter light. Multiple angle light scatter signals are collected an measured. Measures cellular granularity, nuclear lobularity, and cell surface structure.

1+ - 4+

3.6-10.6 x 10^3/µL.

1.7-7.5 x 10^3/µL.

50-70%.

1.0-3.2 x 10^3/µL.

18-42%.

0.1-1.3 x 10^3/µL.

2-11%

0-0.3 x 10^3/µL.

1-3%.

0-0.2 x 10^3/µL.

0-2%.