Opiate detection in saliva and urine--a prospective comparison by gas chromatography-mass spectrometry

There is an increasing interest in saliva as an alternative analytic body fluid.

This study sought to determine the correlation of opiates analyzed in saliva and corresponding urine.

A total of 130 adequate and 24 inadequate samples were collected from patients participating in drug withdrawal therapy. To obtain saliva from the oral cavity, a newly developed collection device (Clin Rep), consisting of a treated cotton roll and a centrifugation vial with a filter inset, was tested. For the preparation of a purified solution of urine, liquid extraction was used. Solid phase extraction was utilized to prepare the saliva samples. For the detection by gas chromatography-mass spectrometry, an appropriate derivatization was necessary using N-methyl-N-(trimethylsilyl)trifluoroacetamide. The retention times were compared with defined standard solutions. The obtained mass spectra showed a characteristic fragmenting pattern and offered a reliable identification.

The concordance of the analytic results of the saliva samples with urine was 93% for a decision limit of 100 ng/mL and 98% for a decision limit of 300 ng/mL (DHHS opiate cutoff) in urine.

Saliva, of adequate amount in 85% of samples, may be appropriate for analysis of drugs of abuse.