Biology Reference
In-Depth Information
enough to detect either rHuEPO or recombinant human growth hormone
(rHuGH) in human urine. Sonksen and colleagues attempted find a group of
blood parameters that would indicate recent use of rHuGH. After collecting
baseline blood samples, they administered rHuGH for several days and moni-
tored serum concentrations of six substances known to be influenced by
rHuGH [48] A composite score indicative of recent use of rHuGH was devel-
oped. The results showed good separation between the scores of the placebo-
treated and rHuGH-treated subjects. The investigators intend to expand the
studies to a much larger number of subjects and to determine the variability of
the markers in various ethnic groups. The hope is to find a composite score that
is so convincing that the indirect test is considered definitive. Until 2000, no
practical direct test existed for rHuEPO; therefore, certain sports implemented
indirect tests to identify potential users of rHuEPO.
Indirect tests for doping with erythropoietic proteins
The hematocrit 'health' test
The International Cycling Union, concerned that EPO had pervaded elite com-
petition, declared that athletes could not compete with a hematocrit >50% and
>47%, for men and women, respectively [49, 50]. The International Ski
Federation implemented a similar rule based on hemoglobin values exceeding
185 g/L (men) or 165 g/L (women). One strategy was to determine the values
immediately before an event and withhold the athletes from competition if the
limits were exceeded. The hematocrit cut-off values have been changing, but
generally they are 50% for men and 47% for women. The hematocrit test has
been called a “health test” because it is considered dangerous for an athlete to
compete if the hematocrit is greater than the cut-off. The term “health test”
pre-empts legal action because the athlete is not declared a drug user, he/she is
only unable to compete. The ban on competition is lifted after 15 days, pro-
vided that the hematocrit has decreased to acceptable values.
Aside from the health issue, the argument in favor of a hematocrit test is that
by imposing an upper limit, the test prevents excessive use of rHuEPO. An
argument against the hematocrit test is that it would discriminate against indi-
viduals who have naturally high hematocrit values [51, 52]. Partially counter-
ing this argument is the finding that of 334 hematocrits determined on 34 pro-
fessional cyclists before rHuEPO was available, the values ranged from 39%
to 48% (mean: 43%) [53]. In addition, a protocol was developed to determine
if an athlete's hematocrit naturally exceeds 50%. Postural changes in hemat-
ocrit are avoided by taking samples after sitting for 15 min. Increased hemat-
ocrits due to dehydration have not been a significant problem [30]. Despite the
controversial nature of the test, its use is having the intended effect:
Hemoglobin values among elite cross-country skiers increased dramatically
from 1994 to 1996 and declined after the test was implemented [54].
