The A and B tests are not the same test run by different technicians, but test different entities on the HCG. The second test, thus acts as the confirmatory test. This is why the validity of the test is accepted by the NFL. This is the exact same protocol used with confidence by The World Anti-Doping Association.
The NFLs HCG urine test is run using a very accurate method called immuno-assay. This is a test that will be determined as positive at 5 miu/l or higher. The way this test is run is that antibodies, created in the laboratory to attach only to a specific target (antigen), in this case HCG (much like antibodies attach to a bacterial target) is mixed with a persons urine. The complex that is formed if there is HCG in the urine is then reported if it meets the detection tolerance of the test (in this case 5 miu/l). The NFL first tests the A specimen of the split sample. IF it is reported positive, the B specimen will be run by the same laboratory, but by another technician. Furthermore, to afford the player added accuracy insurance, a different antibody is used in each of the 2 specimens, differing in the fact that one is trained to seek out one specific component (epitome) on the HCG while the other is trained to seek out a separate and distinct specific component on the HCG. After a positive A specimen is obtained, if the B specimen is negative or questionable (for example, on the cusp of almost being positive), the player is given the benefit of the doubt........and the cumulative testing is considered negative. It should be kept in mind that the lower limits of the positive 5 miu/l level is considered well above levels expected in the urine.
