Baseball and its players' union say urine samples in drug tests may be subject to additional analysis even if the ratio of testosterone to epitestosterone is under the level that typically is considered a positive.
The joint statement Monday came five days after San Francisco outfielder Melky Cabrera, the All-Star game MVP, was suspended for 50 games for testosterone.
Most drug-testing programs consider a T/E ratio of 4-to-1 or higher to be a positive. But for several years in baseball, the policy has been that samples are potentially subject to further scrutiny if the ratio is below 4-to-1. The usual ratio in adults is 1-to-1.
''The fact that a sample has a T-E ratio below 4:1 does not mean that sample is free from further analysis,'' the joint statement said. ''The characteristics of every sample, including the T/E ratio, are analyzed at the WADA-certified laboratory in Montreal and the laboratory determines which samples are subjected to Carbon Isotope Ratio (CIR) testing. All samples with a T/E ratio above 4:1 are subjected to CIR but so are many samples with a T/E ratio less than 4:1.''
The CIR test determines if testosterone came from outside the body.
''The procedures used in the Montreal laboratory make more extensive use of CIR than those used in other labs and there is no doubt that baseball's program detects testosterone positives that other programs would fail to detect,'' Christiane Ayotte, director of the World Anti-Doping Agency-certified laboratory in Montreal, said in a statement released by MLB and the union.