Within-subject variation in hemoglobin mass in elite athletes.

EASTWOOD, A., K. SHARPE, P. C. BOURDON, S. M. WOOLFORD, P. U. SAUNDERS, E. Y. ROBERTSON, S. A. CLARK, and C. J. GORE. Within-Subject Variation in Hemoglobin Mass in Elite Athletes. Med. Sci. Sports Exerc., Vol. 44, No. 4, pp. 725-732, 2012. Illicit autologous blood transfusion to improve performance in elite sport is currently undetectable, but the stability of longitudinal profiles of an athlete's hemoglobin mass (Hb(mass)) might be used to detect such practices. Purpose: Our aim was to quantify within subject variation of Hb(mass) a in elite athletes, and the effects of potentially confounding factors such as reduced training or altitude exposure. Methods: A total of 130 athletes (43 females and 87 males) were measured for Hb(mass) an average of six times during a period of approximately 1 yr using carbon monoxide rebreathing. Linear mixed models were used to quantify within-subject variation of Hb(mass) and its associated analytical and biological components for males and females, as well as the effects of reduced training and moderate altitude exposure in certain athletes. Results: The maximum within-subject coefficient of variation (CV) for Hb(mass) a was 3.4% for males and similar to 4.0% for females. The analytical CV was similar to 2.0% for both males and females, and the long-term biological CV, after allowing for analytical variation, was 2.8% for males and 3.5% for females. On average, self-reported reduced training resulted in a 2.8% decrease in Hb(mass) and altitude exposure increased Hb(mass) by 1.5% to 2.9%, depending on the duration and type of exposure. Conclusions: The within-subject CV for Hb(max) of 4% indicates that athletes may experience changes up to similar to 20% with a 1-in-1000 probability. Changes of this magnitude for measures taken a few months apart suggest that Hbinus, has a limited capacity to detect autologous blood doping. However, changes in Flb, may be a useful indicator when combined with other measures of blood manipulation.