Gastrointestinal Symptoms, Fluid Loss and Haematological Parameters

Antidoping testing, especially determination of blood manipulation, relies on a variety of laboratory methods, procedures, and expertise. Schumacher and Pottgiesser [6] are to be commended for their scientific and ethical merit in reporting on research into the parameters included in the Athlete Biological Passport (ABP) adopted by the International Cycling Union for identifying suspected blood manipulation and sanctioning athletes whose haematological profiles indicate a very high probability of abnormal variability. The statistical Bayesian-like method, now referred to as “adaptive” and initially introduced as an antidoping model with an abridged scientific literature [4] [9], has been criticized for the inaccuracy of its sources [1]. In previous papers on reticulocytes and the preanalytical phase, Schumacher and Pottgiesser applied the statistical model to set the ABP on firmer scientific ground [7] [8].

In contentious cases of alleged anomalous haematological profiles, a number of reasons have been given for justifying haemoglobin (Hb) and reticulocyte (Ret) variation over time. These explanations are sometimes difficult to evaluate and interpret, however, because they refer to blood drawings taken many months earlier or are based on declarations by the athlete and team personnel. Possible haemoconcentration due to loss of fluids during severe episodes of diarrhoea and/or vomiting, which commonly affect professional athletes during the competition season, can lead to increased Hb concentration, whereas Ret, expressed as a percentage, remains substantially unchanged. Haemoconcentration can also be a cofactor of increased Hb linked to other environmental causes, including natural or artificial altitude exposure and physiological imbalances between plasma and erythrocyte volumes during detraining, when the plasma volume decreases with discontinuation of training and competition. Moreover, the frequent gastrointestinal symptoms are not always linked to an infection or an increase of leukocytes [3].

In their article, Schumacher and Pottgiesser describe 5 cases of athletes seen at an outpatient clinic for severe gastrointestinal (GI) symptoms. As they denied possible haemoconcentration owing to fluid loss, the GI symptoms, though severe, do not fully explain the sudden increase in Hb.

To facilitate interpretation of the data, some points need to be clarified:

the time elapsed between the previous blood drawing and that obtained during symptoms. In Figures 6 generated by the ABP software the time interval is not defined. The actual values of Hb should differ at the various time points, especially for the days just before symptom onset; the amount of fluid loss is not defined. This makes it difficult to calculate, even approximately, this finding in relation to symptom severity; the professional athletes observed at the outpatient clinic were most likely controlled correctly and treated with fluid reintegration: this crucial point deserves fuller description; for instance, knowing the values for Hb concentration and possible changes after fluid reintegration are of great importance. In fact, intravenous fluid reintegration is prohibited by sport antidoping agencies, as the procedure can alter haematological parameters; if the parameters were measured with the athletes in clinostatism, this could have influenced the equilibrium between plasma and erythrocyte volumes 5; Hb variability can also be linked to different periods of the competition season in cyclists 2: the average value reported in Table 1 is insufficient to describe Hb modifications in some athletes; it is unclear how the thresholds (upper and lower individual limits in Fig. 1a–e) were defined for the first blood drawing of the profiles. Following the seminal document for interpreting ABP 10, the values should be derived from a modal value of 146 g/L for non endurance athletes and 148 g/L for endurance athletes. For example, for athlete no. 3, the minimal value for the second drawing should be 133.6 g/L and the maximal 169 g/L; however, a standard deviation of ±30 g/L is used for both the categories.

More detailed explanations are needed to gain a better understanding of the reported findings. That said, studies on changes in athletes’ blood parameters during the competition season and during illness are of vital importance, especially for shedding light on the use of prohibited drugs or procedures.

References

• 1 Banfi G, Lombardi G, Colombini A, Lippi G. A world apart: Inaccuracies of laboratory methodologies in antidoping testing.  Clin Chim Acta. 2010;  411 1003-1008
• 2 Banfi G, Lundby C, Robach P, Lippi G. Seasonal variations of haematological parameters in athletes.  Eur J Appl Physiol. 2010;  [Epub ahead of print]
• 3 Banfi G, Marinelli M, Bonini PA, Gritti I, Roi GS. Pepsinogens and gastrointestinal symptoms in mountain marathon runners.  Int J Sports Med. 1996;  17 554-558
• 4 Robinson N, Sottas PE, Mangin P, Saugy M. Bayesian detection of abnormal haematological values to introduce a no-start rule for heterogeneous populations of athletes.  Haematologica. 2007;  92 1143-1144
• 5 Schmidt W, Biermann B, Winchenbach P, Lison S, Böning D. How valid is the determination of hematocrit values to detect blood manipulations?.  Int J Sports Med. 2000;  21 133-138
• 6 Schumacher YO, Pottgiesser T. The impact of acute gastroenteritis on haematological markers used for Athletes Biological Passport – report of 5 cases.  Int J Sports Med. 2010;  [Epub ahead of print]
• 7 Schumacher YO, Sahm D, Baumstark MW, Pottgiesser T. Reticulocytes in athletes: Longitudinal aspects and the influence of long- and short-term exercise.  Drug Test Anal. 2010;  2 469-474
• 8 Schumacher YO, Wenning M, Robinson N, Sottas PE, Ruecker G, Pottgiesser T. Diurnal and exercise-related variability of haemoglobin and reticulocytes in athletes.  Int J Sports Med. 2010;  31 225-230
• 9 Sottas PE, Robinson N, Saugy M, Niggli O. A forensic approach to the interpretation of blood doping markers.  Law Prob Risk. 2008;  7 191-210
• 10 Swiss Laboratory For Doping Analyses . Athlete's Hematological Passport Interpretation Technical Document, Version 2.09, 2009; 

Correspondence