THE ANALYSES WERE PART OF A LABORATORY PROFICIENCY TESTING PROJECT. EACH SAMPLE CONTAINED DL-METHAMPHETAMINE-HCL, EPHEDRINE SULFATE, LACTOSE, AND ANHYDROUS SODIUM CARBONATE. THE LABORATORIES WERE TOLD ONLY THAT THE SAMPLE WAS A STREET BUY AND WERE ASKED TO PROVIDE ALL THE QUALITATIVE AND QUANTITATIVE INFORMATION THEY COULD AND TO INDICATE THEIR METHODS OF ANALYSIS. OF THE RESPONDING LABORATORIES, 87 (59.6 PERCENT) IDENTIFIED BOTH CONTROLLED SUBSTANCES; 31 (21.2 PERCENT) IDENTIFIED ONLY METHAMPHETAMINE; 17 (11.6 PERCENT) IDENTIFIED ONLY EPHEDRINE; 7 (4.8 PERCENT) FOUND NO CONTROLLED SUBSTANCE; AND 4 (2.7 PERCENT) IDENTIFIED OTHER AMPHETAMINES. EIGHTY-THREE (56.8 PERCENT) OF THE LABORATORIES REPORTED FINDING CUTTING AGENTS. DETAILS OF THE SAMPLE SUPPLIER'S CHARACTERIZATION OF THE SAMPLE, RESPONSES OF REFEREE LABORATORIES, AND THE METHODS AND FINDINGS OF TEST LABORATORIES ARE PRESENTED IN TABLES. BREAKDOWNS OF RESPONSES FROM INDIVIDUAL LABORATORIES ARE INCLUDED, AS ARE INFORMATON ON SURVEY METHODS AND A COPY OF THE SURVEY INSTRUMENT. OTHER LABORATORY PROFICIENCY TESTS INVOLVING DRUG ANALYSIS ARE REPORTED IN NCJ-47522 (BARBITURATES) AND 47527 (HEROIN AND COCAINE). TESTS INVOLVING OTHER FORMS OF PHYSICAL EVIDENCE ARE REPORTED IN NCJ 47523-47526, 47528-47535, AND 47537-47542. (LKM)