CHARLOTTE, N.C. -- Testing performed by an independent laboratory supported the results that left Sprint Cup driver Jeremy Mayfield indefinitely suspended for failing NASCAR's substance abuse policy, court documents said.
Results of the test and the name of the individual tested were blacked out, but a NASCAR spokesman confirmed they were identical.
The documents, part of NASCAR's response to Mayfield's lawsuit to have his indefinite suspension lifted, show that Medtox Laboratories in Minnesota tested both his "A" and backup "B" samples last week and "confirmed the presence" of a substance that is blacked out in the filing.
NASCAR claims Mayfield tested positive for a "dangerous, illegal, banned substance" and should not be allowed back on the track. It was revealed in open court two weeks ago that the drug was amphetamines.
ESPN the Magazine's Ryan McGee, citing multiple sources, said it was methamphetamines.
Mayfield's attorneys claim that NASCAR's drug testing program does not meet federal workplace guidelines. They argue that Mayfield did not give permission for the "B" sample to be tested after the "A" sample came back positive and that the "B" sample should have been tested at an independent laboratory.
They said since proper procedure was not used and because the "B" sample was compromised when opened, thus not giving Mayfield the opportunity to send it to a second lab, that the entire test should be invalid.
Both samples originally were tested by Aegis Laboratory, the Nashville Tenn.-based facility NASCAR employs to run its testing program. The most recent test was conducted at MedTox Laboratories in St. Paul, Minn.
NASCAR argues that it is not a federal entity and does not have to follow federal guidelines. The NFL and Olympic testing programs also allow the "B" sample to be tested by the same lab as the "A" sample.
All the evidence will be dealt with at a Wednesday hearing in U.S. District Court, where Mayfield is seeking a temporary restraining order that would allow him back in the car, possibly as early as Saturday night's race at Daytona International Speedway.
Mayfield's attorney, Bill Diehl, said the hearing is critical and will determine his course of action moving forward.
If the judge grants the order, Diehl said his next step will be to seek damages Mayfield suffered from being out of the car since the suspension was handed down on May 9. Mayfield in his affidavit said he has lost sponsors and had to lay off 10 employees.
If the order is denied, Diehl plans to go to court to argue whether NASCAR's drug testing policy is fair. He said that process could take more than a year.
Mayfield has denied taking an illegal drug from the outset. He has argued that the positive test resulted from him taking Adderall, which treats attention-deficit hyperactivity disorder, and Claritin D, an over-the-counter allergy medicine.
"I have never taken methamphetamines in my life, and when accused of taking them I immediately volunteered to give another urine sample," he said in the affidavit.
Mayfield's attorneys have affidavits from several experts claiming there are circumstances where Claritin D can produce a positive test for methamphetamines.
Affidavits also have been taken from members of Mayfield's crew stating that he did not put anybody at risk at the time he tested positive.
"I am familiar with the signs of drug use," crew chief Tony Furr said in an affidavit. "Based up on my life experience and observation of Mr. Mayfield he was not under the influence of any mind or cognitive function altering drugs.
"Mr. Mayfield was alert, oriented, fully in control of his faculties, pleasant and in all respects appeared healthy."
NASCAR filed statements from several drivers saying they are not "willing to put my life at risk driving a race car on a NASCAR track with drivers testing positive for drugs that diminish their capacity to drive a race car."
Mayfield has not attempted to enter the No. 41 team -- with J.J. Yeley as the driver -- since the May race at Lowe's Motor Speedway in Charlotte. Mayfield started the No. 41 team this year, with him as the driver/owner.
In the court filings, Mayfield said he and his wife, Shana, have had to borrow money from family and sell personal belongings to meet living expenses.
"I do not understand how or why this is happening to me or my family," he said in the affidavit. "I have always anticipated that I would be able to race for another 10 years, but I believe my career will be effectively over if I am forced to sit out the rest of this season.
"I am afraid that I will have to sell my race team, and I know of no other way to make a living except as a professional race car driver."
David Newton covers NASCAR for ESPN.com. He can be reached at firstname.lastname@example.org. Information from The Associated Press was used in this report.