Haematological modifications after acute exposure to high altitude: possible implications for detection of recombinant erythropoietin misuse

We have evaluated changes in haematological parameters in 24 healthy Western subjects, normally living at sea level, exposed to high altitude during a scientific expedition to the `Pyramid', Italy's National Research Committee (CNR) laboratory located in the Kumbu Valley (Nepal) at 5050 m. Blood samples were collected as follows: (A) at standard conditions (Kathmandu, 1200 m); (B) upon arrival at the Pyramid, after 6 d walking from 2800 m up to 5050 m; and (C) after an 8-d stay at the Pyramid. Haemoglobin concentration (Hb), haematocrit (Hct), red blood cell count (RBC), white blood cell count (WBC) and platelet number (Plt) were measured on the spot, using a portable automatic counter (Coulter ACT8). In addition, sera were cryopreserved in liquid nitrogen for later measurement, in our laboratory in Pavia, of erythropoietin (Epo) and soluble transferrin receptor (sTfr) concentrations (Quantikine ELISARD System), ferritin (ftr) concentrations (electrochemiluminescence immunoassay `ECLIA'; Boehringer Mannheim) and serum iron concentration (BM/Hitachi 717). Changes in Hb, Plt, sTfr, ferritin and sTfr/ftr concentrations between times A and B and between times B and C were statistically significant (Table I). Moreover, we observed a significant increase in Epo levels between times A and B and between times A and C, but not between times B and C. Haematocrits were significantly higher at time C with respect to time A and B. Finally, the sTfr/ftr ratio increased threefold between standard conditions (A) and the departure from the Pyramid (C).