Why does USADA collect a minimum of 90mL of urine during sample collection?

The laboratories test for nearly 200 Prohibited Substances of many different types – from steroids to erythropoietin (EPO). Some tests only require one teaspoon of urine whereas others may require two tablespoons. The approximately quarter of a cup (60 ml) of urine that goes into the “A” bottle are tested initially for all 200 Prohibited Substances. If a suspicious result is detected in the initial testing, the laboratory performs another test to confirm the presence of the Prohibited Substance. There has to be sufficient volume in the “A” bottle to allow all of these tests to be performed. The “B” bottle must also have sufficient urine volume to allow a confirmation test to be performed if needed.