Microhematocrit
A measurement of the relative RBC volume for a (small quantity) volume of whole blood spun down in a capillary tube
Microhematocrit Procedure
The capillary tube with whole blood is spun down in a centrifuge, RBCs pack at the bottom, hematocrit is the percent of the tube filled with RBCs.
What makes up the buffy coat? Is it included in the hematocrit measurement?
WBCs and platelets make up the buffy coat and are not included in the hematocrit measurement.
Why is the rule of three important?
The result has to agree with the rule of three. If it doesn’t, the hemoglobin or hematocrit would be inaccurate.
Difference between microhematocrit and hematocrit?
Microhematocrit is considered the manual version of measuring hematocrit vs hematocrit on the analyzer
Why is the microhematocrit higher than the automatic hematocrit?
Microhematocrit will be a little bit higher than hematocrit because oof the plasma trapped in erythrocytes.
Erythrocyte Sedimentation Rate
Nonspecific screening test indicating inflammation based on how quickly RBCs stack and settle
Increased ESR associated diseases
Kidney disease, pregnancy, rheumatic fever, rheumatoid arthritis, anemia, syphilis, lupus, thyroid disease, elevated room temperature
Decreased ESR associated diseases
Congestive heart failure, hyper viscosity, decreased fibrinogen, polycythemia, sickle cell anemia
Westergren method
uses Na citrate diluent with whole blood, read at 60 minutes
Automated ESR method
on the Alcor, detects rouleaux via flow cell and photometry
Manual reticulocyte count
finds the bone marrow RBC production index, most effective measure of erythropoiesis, counted out of 1000 RBCs
Decreased Retic associated diseases
Aplastic anemia, exposure to radiation, chronic infection, medications, megaloblastic anemia
Increased Retic associated diseases
rapid blood loss, high elevation, hemolytic anemia, medications, pregnancy
Miller eye disc
helps to not count 1000 RBCs, provides standardized area
How to perform a manual retic
Mix equal parts stain and whole blood for the manual retic, count all reticulocytes in the large and small square, count small squares until you get to 112 RBCs
Manual retic formula
Retic % = Retics in large square / (RBCs in small square * 9) * 100 %
What stain is used for the reticulocyte counts?
New Methylene Blue
Microhematocrit: sources of error
not filling the capillary tube, reading the buffy coat, not following the rule of three
ESR: sources of error
not keeping the tube free from vibration, not keeping the tube level, not pushing the blood to the zero mark, not replacing the cap
Manual retic: sources of error
Interferences: nucleated erythrocytes, Howell-jolly bodies, Pappenheimer bodies, cold agglutinins, basophilic stippling, heinz bodies, parasites, autofluorescence
Percent retic, RPI formula
Retic % = Retics in large square / (RBCs in small square * 9) * 100 %
Conditions associated with increased ESR and retic counts
Pregnancy
Hemolytic anemia
Conditions associated with decreased ESR and retic counts
Aplastic anemia / sickle cell anemia
Soucres of error on the hemocytometer
Not evenly distributing the object across the hemocytometer.
Overcrowding the hemocytometer.
Cytospin
concentrates the cells into a smaller area of the slide
Principle of the LAP test
Helps differentiate CML from a leukemoid reaction
Naphthol AS-BI is hydrolyzed by the enzyme at an alkaline pH. The hydrolyzed substrate with a red-violet LB or fast blue BB dye produces a colored precipitate at the site of enzyme activity
Decreased LAP =
Untreated CML
During a Leukemoid reaction LAP changes from…
High normal to increased
High LAP =
Pregnancy, polycythemia vera
Low LAP =
PNH, Sideroblastic Anemia, Myelodysplastic disorders