Laboratory Hematology

Question 1

Etiology of false elevation in the Hemoglobin

Answer 1

1-Overfilling the blood collection tubes

2-Changes in turbidity:( most)
Hyperlipidemia- most common cause
Hyperbilirubinemia- rarely
Hyperleukocytosis
Hyper proteinuria

Usually in these cases the MCHC will also be higher so MCHC is a good test for spurious results

3- increased plasma free hemoglobin- hemolysis

Question 2

Etiology of falsely reduced red blood cells

Answer 2

Low RBC 
Cold agglutinin( high MCV and high MCHC)

Clotting
Capillary sample

Decreased MCV

Question 3

Describe Iron absorption and processing

Answer 3

Dietary ferric iron is converted to ferrous by reductass on the brush border

DMt1- absorbs it across the border
Ferriportin exports it

Converted back to Fe (3+) to be carried around

Hepcidin produced from the liver decreases the iron absorption from the gut- blocks ferroportin.

Question 4

Definitions of lab parameters and calculations 
Hemoglobin 
RBC
MCV
MCH
MCHC

Answer 4

Hemoglobin- mean hemoglobin in whole blood
RBC- number of red cells in whole blood
MCV- the average size of the persons red cells
Hematocrit- packed spun volume made up of red cells MCVx RBC/10
MCH- the average hemoglobin in the red cell= hemoglobin X 10/RBC
MCHC- the average hemoglobin per red cell= hemoglobin X 10/ Hematocrit

Question 5

What causes spurious decrease in the MCHC

Answer 5

Hyperglycaemia in the patients serum or due to contamination

This will cause osmotically the MCV to enlarge and the MCHC to decrease