Int J Sports Med 2014; 35(02): 89-94
DOI: 10.1055/s-0033-1345177
Physiology & Biochemistry
© Georg Thieme Verlag KG Stuttgart · New York

Variability of Serum Markers of Erythropoiesis during 6 Days of Racing in Highly Trained Cyclists

S. C. Voss
1  Anti-Doping Lab Qatar, Doha, Qatar
M. Alsayrafi
1  Anti-Doping Lab Qatar, Doha, Qatar
P. C. Bourdon
2  Aspire Academy, Sport Science, Doha, Qatar
F. Klodt
3  University of Freiburg, Germany
D. Nonis
5  Exercise and Sport Sciences, Università di Milano, Italy
W. G. Hopkins
6  Sport Performance Research Institute of New Zealand, AUT University, Auckland, New Zealand
Y. O. Schumacher
4  Aspetar – Qatar Orthopaedic and Sports Medicine Hospital Doha, Qatar
› Author Affiliations
Further Information

Publication History

accepted after revision 17 April 2013

Publication Date:
18 July 2013 (online)


The athlete biological passport for the fight against doping is currently based on longitudinal monitoring for abnormal changes in cellular blood parameters. Serum parameters related to altered erythropoiesis could be considered for inclusion in the passport. The aim of this study was to quantify the changes in such parameters in athletes during a period of intense exercise.

12 highly trained cyclists tapered for 3 days before 6 days of simulated intense stage racing. Morning and afternoon blood samples were taken on most days and analysed for total protein, albumin, soluble transferrin receptor and ferritin concentrations. Plasma volume was determined via total haemoglobin mass measured by carbon-monoxide rebreathing. Percent changes in means from baseline and percent standard errors of measurement (analytical error plus intra-athlete variation) on each measurement occasion were estimated with mixed linear modelling of log-transformed measures.

Means of all variables changed substantially in the days following the onset of racing, ranging from −13% (haemoglobin concentration) to +27% (ferritin). After the second day, errors of measurement were generally twice those at baseline.

Plasma variables were affected by heavy exercise, either because of changes in plasma volume (total protein, albumin, haemoglobin), acute phase/inflammatory reactions (ferritin) or both (soluble transferrin receptor). These effects need to be taken into consideration when integrating a plasma parameter into the biological passport model for athletes.