- males 40-52%
- females 36-48%
A raised haematocrit
reflects haemoconcentration. This may be relative due to reduced plasma volume,
or absolute (increased red blood cell mass):
- reduced plasma volume
- often result of dehydration e.g. alcohol, diuretic therapy. Also may occur in
acute pancreatitis (there may be a decreased haematocrit in severe haemorrhagic
pancreatitis), Addison's disease (because of water loss)
- increased red
cell mass - primary (polycythaemia rubra vera) or secondary e.g. chronic lung
disease, smoking, altitude, tumours (hepatoma, fibroids, hypernephroma)
increased red cell mass can be assumed when the haematocrit is over 60% in males
and 56% in females (1)
- comparing individuals with a haematocrit which
is in the upper normal range, or slightly elevated to those with a haemocrit values
in the middle or lower part of the normal range
- individuals with a haematocrit
may be associated with an increase in thrombotic events and cardiovascular mortality
Note that normal ranges vary with different commercial
- Pearson, T.C. Evaluation of diagnostic criteria
in polycythemia vera. Seminars in Hematology 2001;38(1 Suppl 2): 21-24.
G.D. Rheological influences on thrombosis. Baillieres Best Practice & Research.
Clinical Haematology 1999;12(3): 435-449.