The interpretation of athlete biological passport (ABP) is strengthened by understanding the natural fluctuations in its biological parameters. Here we have assessed the influence of the menstrual cycle on the hematological module of the ABP. Seventeen women with regular menses were included. Blood samples were collected once a week for two consecutive cycles and analyzed for hematological parameters. Menstrual phases were hormonally determined. The intra‐individual variation in the hematological parameters was similar between the two cycles. Reticulocyte percentage was significantly lower in the follicle phase (median 0.95%) than in the ovulatory (median 1.10%) and luteal phases (median 1.16%), P = 0.006, whereas no differences were found in hemoglobin concentration, hematocrit, red blood cell count, or red blood cell indices. When the values were entered into the ABP model, findings outside the program‐calculated individual thresholds were identified in two participants. One woman showed an atypical low OFF‐score in the last sample collected, mainly because of increased reticulocyte percentage. This was likely a response to treated insufficient iron stores. One woman displayed an atypical hemoglobin value at the lower limit 2 weeks after ovulation, which was likely due to fluctuations in plasma volume. In conclusion, the ABP parameters in general are stable throughout the menstrual cycle. Significant differences between the menstrual phases were found in reticulocytes; however, the variation was not related to findings outside the individual thresholds, except in one individual. Moreover, our results highlight the importance of having information about iron supplementation available when evaluating hematological passports.

The interpretation of the steroidal module of the Athlete Biological Passport (ABP) in female athletes is complex due to the large variation of the endogenous urinary steroids. The menstrual cycle seems to be one of the largest confounders of the steroid profile. The duration of the different phases in the menstrual cycle differs between women and is difficult to predict only by counting days after menstruation. Here, we have determined the follicle, ovulation, and luteal phases, by assessing the menstrual hormones in serum samples collected from 17 healthy women with regular menses. Urine samples were collected three times per week during two consecutive cycles to measure the urinary steroid concentrations used in the ABP. The metabolite that was mostly affected by the menstrual phases was epitestosterone (E), where the median concentration was 133% higher in the ovulation phase compared to the follicle phase (p < 0.0001). The women with a large coefficient of variation (CV) in their first cycle also had a large CV in their second cycle and vice versa. The inter‐individual difference was extensive with a range of 11%–230% difference between the lowest and the highest T/E ratio during a cycle. In conclusion, E and ratios with E as denominator are problematic biomarkers for doping in female athletes. The timing of the sample collection in the menstrual cycle will have a large influence on the steroid profile. The results of this study highlight the need to find additional biomarkers for T doping in females.

Objective.The aim of this study was to investigate the hematopoietic profile in AAS abusers, during or short after their last abuse and approximately six months later. Moreover, we studied if supraphysiological doses of testosterone influence the concentration of hemoglobin and erythropoietin in healthy volunteers.Design and Methods. Subjects (N=31) were recruited through an antidoping hotline. The hematological profile was measured when the subjects entered the study and approximately 6 months later. Testosterone enanthate (500 mg) was administered to healthy volunteers (N=24). Gene expression was studied in human hek293 cells exposed to 1 μM testosterone.Results.Decreased levels of hemoglobin, erythrocyte volume fraction, and erythrocyte counts were observed after 6 months without the use of AAS. Results in volunteers show that hemoglobin increased 3% four and 15 days after testosterone administration, whereas EPO was significantly increased by 38% four days after dose. Agreeingly,in vitrostudy shows that testosterone induces the mRNA level of EPO with 65% after 24-hour exposure.Conclusion. These results indicate that supraphysiological doses of testosterone may cause a perturbation in the hematopoietic profile. This is of interest in relation to the adverse cardiovascular effects observed in AAS abusers.

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