Audran et al used the ratio of the serum soluble transferrin receptor to serum protein concentration to detect an athlete who is using recombinant erythropoietin (EPO) as a doping agent.
Advantages of ratio:
(1) Serum protein controls for hemoconcentration.
(2) Serum ferritin levels may be affected by concomitant iron therapy.
Parameters:
(1) soluble transferrin receptor (STfr) in mg/L
(2) serum protein in g/L
ratio of the soluble transferrin receptor to serum protein =
= (concentration of STfr) / (serum protein) * 1000
Interpretation:
• The normal ratio is usually < 100.
• Doping with recombinant erythropoietin results in an elevation of the ratio.
Criteria of Audran et al for EPO doping
(1) hematocrit increased (in the absence of dehydration)
