Historical QOD 11/26/08: Which of the following findings suggests heroin use rather than codeine use? A. Serum morphine:serum codeine <1 B. Serum morphine:serum codeine > 1 C. Urine morphine:urine codeine <1 D. Urine morphine:urine codeine > 1 E. Negative 6 acetylmorphine (6-AM) in the urine
B. Serum morphine to serum codeine ratio above unity (ie greater than 1) suggests heroin use. Positive 6-AM indicates heroin use, though it has low sensitivity as it is present for only a short time frame and thus difficult to detect.
Ceder G, Jones AW. Concentration ratios of morphine to codeine in blood of impaired drivers as evidence of heroin use and not medication with codeine. Clin Chem. 2001 Nov;47(11):1980-4. PMID: 11673366.