Biological and radiological investigations in patients with an increased red blood cell mass: Which are needed? Which are useful? which are unnecessary?
A few simple, low-priced, outpatient investigations, including an upper abdominal ultrasonography, a measurement of the arterial oxygen saturation and, in some cases, a leukocyte alkaline phosphatase score (LAP) suffice to find out the etiology of an increased red cell mass in most patients. The diagnosis of polycythemia vera (PV) could be accepted in patients with an increased red cell mass if the spleen is enlarged and if the arterial oxygen saturation is normal, although the latter measurement may not be required in typical cases. If the spleen is not enlarged, the diagnosis of PV could be accepted if, in addition, the leukocyte or thrombocyte count is increased. An elevated LAP score also points to the diagnosis of PV, provided fever or inflammation are not present. If, at that stage, an etiologic diagnosis has not been made, smoker's polycythemia should be considered and excluded. The next step should include a serum erythropoietin assay and culture of erythroid stem cells before performing investigations aimed at ruling out the many conditions associated with secondary polycythemia.
Delannoy
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Cliniques Universitaires Saint Luc, Service d'Hématologie, Bruxelles, Belgique.
D000469:Alkaline Phosphatase / Q000097:blood; D004906:Erythrocyte Count; D006801:Humans; D007962:Leukocytes / Q000201:enzymology; D011087:Polycythemia Vera / Q000175:diagnosis* / Q000209:etiology; D011237:Predictive Value of Tests; D011379:Prognosis; D013163:Splenomegaly / Q000175:diagnosis; D014805:Vitamin B 12 / Q000097:blood
D000469:Alkaline Phosphatase; D014805:Vitamin B 12