2 Examination of Blood and Marrow Cells Flashcards
Red cell parameters that are directly measured
mean cell volume [MCV]
red cell number
hemoglobin concentration
red cell distribution width [RDW]
Red cell parameters that are derived
hematocrit
mean cell hemoglobin [MCH]
mean cell hemoglobin concentration [MCHC]
Formula for hematocrit
(Hct [L/100 L] =RBC [× 10−12/L] × MCV [fL]/10)
TRUE OR FALSE
The hemoglobin determination now is preferred to the hematocrit, because it is measured directly and is the best indicator of the oxygen-carrying capacity of the blood
TRUE
The hemoglobin determination now is preferred to the hematocrit, because it is measured directly and is the best indicator of the oxygen-carrying capacity of the blood
To determine hemoglobin concentration in the blood, red cells are lysed and hemoglobin variants are converted to the stable compound cyanmethemoglobin for quantification by absorption at _______
540 nm
All forms of hemoglobin are readily converted to cyanmethemoglobin except_____________________, which is rarely present in significant amounts.
Sulfhemoglobin
In practice, the major interference with hemoglobin measurement is__________________, but newer instruments identify and minimize this interference.
Chylomicronemia
Any child with a hemoglobin level below ______ should be considered anemic
11 g/dL
TRUE OR FALSE
When it comes to gender variation in hemoglobin, it has been found that adult men have significantly lower red blood cell counts, hemoglobin levels, and hematocrits than women
FALSE
When it comes to gender variation in hemoglobin, it has been found that adult women have significantly lower red blood cell counts, hemoglobin levels, and hematocrits than men
An estimate of the variance in volume within the population of red cells, which is expressed as 1 SD of red cell volume measurements divided by the MCV.
Red Cell Distribution Width
A biomarker predicting morbidity and mortality in a broad variety of clinical settings, such as angina/myocardial infarction; heart failure; trauma; pneumonia; sepsis;intensive care treatment; renal and liver disease; and in the general population.
Red Cell Distribution Width
It is at least as sensitive as the MCV in detecting iron-deficiency states
An advantage is the consistency across different analyzer types, as it is derived from two of the most accurately measured parameters: hemoglobin and red cell count.
Mean Cell Hemoglobin
Permits an estimate of marrow erythrocyte production, which is useful in evaluating the pathogenesis of anemia by distinguishing inadequate production from accelerated destruction
Reticulocyte Count
An early sign of marrow recovery from cytotoxic therapy or treatment for nutritional anemias
Increase in the immature (highest RNA content) reticulocyte fraction
May be a better predictor of depleted marrow iron stores than traditional serum iron parameters in nonmacrocytic patients, and is a more sensitive predictor of iron deficiency than hemoglobin for screening infants and adolescents for iron deficiency.
CHr
Conditions wherein automated leukocyte counts may be falsely elevated
cryoglobulins or cryofibrinogen;
clumped platelets or fibrin from an inadequately anticoagulated or mixed sample,
ethylenediaminetetraacetic acid (EDTA)-induced platelet aggregation,
nucleated red blood cells,
nonlysed red cells
Conditions wherein automated leukocyte counts may be falsely decreased
EDTA-induced neutrophil aggregation
Causes of falsely decreased platelet counts
Incomplete anticoagulation of the sample (sometimes accompanied by small clots in the specimen or fibrin strands on the stained film)
Platelet clumping (pseudothrombocytopenia) or “satellitism” (adherence of platelets to neutrophils)
Aggregation induced by nonpathogenic antibodies recognizing platelet adhesion molecule epitopes exposed as a result of chelation of divalent cations in the anticoagulated sample
Compared to sodium EDTA anticoagulant, is reported to more effectively inhibit platelet aggregation in these patients and provide an accurate platelet count
Magnesium EDTA anticoagulant
Causes of falsely elevated platelet count
Severe microcytosis
Cryoglobulins
Leukocyte cytoplasmic fragmentation
Platelet count may be roughly estimated (FORMULA)
2000 times the number of platelets in 10 consecutive oil immersion (1000×) fields
A marker of marrow megakaryocytopoiesis and is proposed as a way of differentiating decreased production of platelets from circulatory destruction or removal as a cause of thrombocytopenia, in an analogous fashion to the use of the reticulocyte count
Reticulated platelets or immature platelet fraction
The most common error in blood film interpretation
Selection of a portion of the blood film for analysis that is too thick or too thin for proper morphologic evaluation
The optimal portion of the film is examined at ______________ to systematically assess the size, shape, and morphology of the major cell lineages.
high magnification (×1000, oil immersion)
TRUE or FALSE
The normal-sized erythrocyte is about the diameter of the nucleus of a small lymphocyte.
TRUE
The normal-sized erythrocyte is about the diameter of the nucleus of a small lymphocyte.
A more sensitive measure of red cell volume than of the red cell diameter
MCV
Term that describes variation in erythrocyte size, and is the morphologic correlate of the RDW.
Anisocytosis
Early (“shift” or “stress”) reticulocytes (ie, those with the most residual RNA) appear in stained films as large, slightly bluish cells, referred to as
Polychromatophilic cells
Term used to describe variations in the shape of erythrocytes
Poikilocytosis
Difference between a platelet that overlie an erythrocyte vs an inclusion body or a parasite
The differentiation depends on the observation of a halo around the platelet, determination that it lies above the plane of the erythrocyte, and observation of the characteristics of a normal platelet in the “inclusion.”
The nucleus of 1% to 16% of the neutrophils from females may have an appendage that is shaped like a drumstick and is attached to one lobe by a strand of chromatin.
It represents the _______________________
inactive X chromosome of the pair
The predominant type of lymphocyte in normal blood, is round and contains a relatively large, round, densely stained nucleus
The cytoplasm is scanty and stains pale to dark blue.
small lymphocyte