Experience with a Urine Opiate Screening and Confirmation Cutoff of 2000 ng/mL

Published: Journal of Analytical Toxicology, Volume 23, Number 6, October 1999, pp.549-551

Technical Note

Experience with a Urine Opiate Screening and Confirmation Cutoff of 2000 ng/mL
Albert D. Fraser and David Worth

Until recently, most laboratories used an opiate immunoassay screening and confirmation cutoff value of 300 ng/mL for codeine and morphine detection by gas chromatography–mass spectrometry (GC–MS). The cutoff value for opiates was increased to 2000 ng/mL or higher in various laboratories because of concerns that small doses of codeine and foods containing poppy seeds would give a positive opiate-screening result. Workplace drug-testing programs in the U.S. raised the opiate cutoff value to 2000 ng/mL on 30 November 1998. The objective of this study is to describe the results of opiate testing of 8600 urine specimens collected over 24 months with a 2000-ng/mL screening and confirmation (codeine and morphine) cutoff value. Specimens were screened by the EMIT®dau™ opiate assay using an in-house 2000-ng/mL morphine calibrator. Presumptive positive findings (N = 621) were analyzed quantitatively by GC–MS for codeine and morphine. One hundred and eighty six urine specimens were positive for codeine and morphine (> 2000 ng/mL), 298 specimens were positive for codeine only (> 2000 ng/mL) and 26 specimens were positive for morphine only (> 2000 ng/mL). All remaining specimens had codeine and morphine values < 2000 ng/mL. The codeine and morphine confirmation rate in this program reduced from 7.1% in 1994–1996 (300-ng/mL cutoff) to 2.1% in 1997–1998 with a 2000-ng/mL cutoff value. The codeine-only confirmation rate lowered from 6.6% (300-ng/mL cutoff) to 3.4% (2000-ng/mL cutoff). It was concluded that increasing opiate screening and codeine and morphine confirmation cutoff values led to > 300% reduction in the confirmed-positive rate for codeine and morphine and a 47% reduction in codeine-only confirmations in a urine drug-testing program where codeine was the major opiate used.

Reproduction of editorial content of this journal is prohibited without publisher’s permission.

This article is available in its entirety by fax for $4.00 per page.
Visa or MasterCard accepted.

To order electronically click here
or call: 847-647-2900 ext. 1323
or fax request to: 847-647-1155.

Please indicate JAT volume and issue along with page numbers.