Today’s edition of La Gazzetta dello Sport published a short article of just 8 lines: 5 athletes of the French national cross country ski team (Vittoz, Gaillard, Ambrosetti, Soubeyrand, Bailly), returning from a period of training at altitude, have been tested and found with Hb values superior to the limit (17g%). The FIS will decide whether to sanction them with a 5-day stop or grant a dispensation. 

What would happen if the protagonists of such an episode were 5 cyclists of the same team, returning from an altitude training camp just immediately before the start of the TdF? 

It is rather a frequent evidence and a normal fact for athletes that often train at altitude to have Hb concentrations higher than 17g%: indeed it would be abnormal to see low values, which might point to some nutritional deficiency (iron, folic acid, copper, protein). 
When such athletes come back to sea level, their reticulocytes quickly drop to values that are below the norm, while Hb decreases at a much slower rate, with the result that the Australian OFF-score formula jumps to “suspicious” levels. 

A similar scenario can happen when athletes have arrived at altitude from a few hours: Hb increases by 1-2g% because of the physiological hemoconcentration: the need to urinate frequently and copiously, especially during the night, is proof of the organism trying to compensate the oxygen reduction in the air, by decreasing the liquid part in the blood and increasing the Hb concentration. 
The reticulocytes increase only after 2-4 days of altitude sojourn, therefore the high value in Hb plus the normal value in reticulocytes make the OFF-score jump to numbers that some might interpret as “suspicious”. 

Testing hematic parameters in the morning on cyclists who slept at altitude after a mountain stage could result in altered values: this might explain the higher than expected levels in Hb and Hct in the athletes tested for example in Madonna di Campiglio in the Giro of ’99. 

Also rest days in stage races could determine “abnormal” oscillations in the hematic parameters, due to variations in the plasma volume.