The OFFscore function computes the value of the OFF-hr
score (or OFF score), a combination of the haemoglobin level and
the percentage of reticulocytes, used for detecting blood doping.
OFFscore(haemdata = NULL, HGB = NULL, RETP = NULL)a vector or data frame containing (at least) the 2 haematological variables, either with the same names as the parameters below, or (not recommended) without names but in the same order as the parameters.
level of haemoglobin HGB [g/dL]
percentage of reticulocytes [%]
value of the OFF score.
The OFF-hr score is defined as 10*HGB [g/dL] - 60*sqrt(RETP [%]).
It is one of the parameters of the Athlete Biological Passport (ABP) program managed by the World Anti-Doping Agency (WADA), and is routinely used to identify athletes who use a substance prohibited by anti-doping rules (see e.g. https://jurisprudence.tas-cas.org/Shared%20Documents/4006.pdf).
The rationale for using this score for detecting blood doping is the following: if a manipulation (use of transfusion or of erythropoietic stimulating agents (ESA) such as recombinant human erythropoietin (rhEPO)) increases the number of circulating red cells (and thus increases the level of haemoglobin), the organism will react by stopping its own production of red blood cells. This negative feedback will be observed in the reduced percentage of reticulocytes (immature red blood cells). Such a combination of elevated HGB and reduced RETP, which will produce a high OFF score, is found neither naturally, nor as the consequence of a medical condition, and is thus indicative of doping.
The OFF score will pick up both withdrawal of blood (which induces a reduction in haemoglobin, a rise in reticulocytes, and thus a rise of RETP and a reduction of OFF score), and its re-infusion (HGB concentration increases, number of reticulocytes and RETP decrease, and OFF score increases).
Gore, C.J., R. Parisotto, M.J. Ashenden, et al., Second-generation blood tests to detect erythropoietin abuse by athletes. Haematologica, 2003. 88(3): p. 333-44.
# NOT RUN {
OFFscore(HGB=14.6, RETP=0.48)
data(blooddoping)
OFFscore(HGB=blooddoping$HGB, RETP=blooddoping$RETP)
# }
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