"Rapist in a Glass" (The Forensic Echo, October 1997) unfairly criticizes the drug testing performed by ElSohly Laboratories.

Anyone reading the quote attributed to the Dr. Lionel Raymon can only conclude that he questions the validity of the ElSohly Laboratories testing program. This is not true. At the time Dr. Raymon was interviewed by the authors, the ElSohly methodology was not yet published.

The ElSohly Laboratories assay to detect flunitrazepam metabolites is the most sensitive and accurate available at this time. Through a substantially more sensitive gas chromatography/mass spectrometry (CC/MS) assay (1 ng/ml of detection) applied to every urine sample, ElSohly Laboratories is able to test for flunitrezapan (Rohypnol) and detect its metabolites, if present in samples collected within 72 hours of ingestion of as little as 1 mg of the drug.

Dr. Raymon's statements were made in response to questions of a hypothetical nature. The quoted figure of 43% refers to the assay used by Dr. Raymon in his initial testing of urine samples from drivers suspected of driving under the influence in Florida. Using his own lab tests as a n example, Dr. Raymon found that commonly used immunoassay cutoff values of 200 ng/ml or 300 ng/ml to screen for benzodiazepines would have missed 43% of Dr. Raymon's 7-aminoflunitrazepam containing samples. Dr. Raymon, therefore, modified his assay to improve the chances of picking up positive specimens on the initial screen.

The Echo article was recently cited at a sexual assault conference in Maine to criticize the ElSohly assay and advocate against ElSohly's testing service. It is unfortunate that this would effectively limit the availability of this resource to the groups that need it the most-that is, law enforcement and rape crisis centers.

Editor's reply: Thank you for releasing the details of your assay. Public disclosure always promotes understanding.