Determination of tricyclic antidepressants for ED analysis.

Both the Biosite Triage (Biosite Diagnostics, San Diego, CA) method and the Du Pont aca (Du Pont Company, Wilmington, DE) method give qualitative tricyclic antidepressant (TCA) results to aid in the diagnosis of a TCA overdose. The Triage method uses urine samples and the aca uses serum samples. Although the cutoff values vary considerably between the two methods, the Triage results agreed well with the aca results. The Triage test has an advantage in instrument maintenance and time savings, allowing a reduction in turn-around time for our emergency department. Both urine and serum samples were obtained from 44 patients who were admitted to the emergency department with a diagnosis of "possible tricyclic overdose." Discrepancies between the two methods were resolved by thin layer chromatography (Toxi-Lab, Ansys, Inc, Irvine, CA). Both methods were in agreement with the exception of five patients' samples. In this study, the Triage method allowed for detection of TCA using urine that is simple for the user and yielded higher sensitivity and specificity results compared with the Du Pont aca method.

Accuracy of common drug screen tests.

Forty consecutive urine specimens, obtained from patients seen in the emergency center, positive for either cocaine and/or marijuana, were analyzed using five methods of analysis. A new latex agglutination inhibition assay, Abuscreen OnTrak, (Roche Diagnostic Systems, Nutley, NJ), was compared with four other drug abuse assays: mass spectrometry, (Hewlett-Packard Co, Richardson, TX); an automated homogeneous enzyme immunoassay technique, ETS System, (Syva Co, Palo Alto, CA); a manual enzyme multiplied immunoassay technique; EMIT-st, (Syva); and a fluorescence polarization immunoassay, TDx, (Abbott Laboratories, Chicago, IL). For statistical purposes, mass spectrometry was the reference point for the presence or absence of a specific substance. All instrument sensitivities, with the exception of mass spectrometry, were set with the same "cut off" point of 100 micrograms/L for marijuana and 300 micrograms/L for cocaine and its metabolites. Efficiency in the detection of cocaine and its metabolites was 95% by all methods. Efficiency for the detection of marijuana and its metabolites ranged from 70% (Roche's OnTrak) to 90% (Syva's ETS). Simple to use, assays of minimal cost are presently available for rapid, accurate drug of abuse screening.

Hospital-based toxicology: patterns of use and abuse.

We examined 949 consecutive toxicology requests to determine (a) the identity and relative frequency of the most commonly detected drugs in our hospital population; (b) degree of concordance between clinical impression and laboratory analysis; (c) influence of age and sex upon the numbers and results of toxicologic analyses; (d) temporal pattern of our annual toxicology case-load; (e) temporal and sexual distribution of various common drugs; (f) drugs most often found together; and (g) frequency with which inappropriate toxicology request were received. Laboratory analysis agreed with clinical impression in only 17.4% of cases. Age and sex correlated with the detection of specific drugs. But for benzodiazepines, no consistent temporal pattern was present regarding either type or number of drugs detected. Certain days of the week demonstrated a statistically significant effect upon the number of toxicology requests received, while seasons, holidays, and lunar phases had no influence. Inappropriate requests comprised 9% of the total annual toxicology caseload.

A commercial enzyme immunoassay method (EMIT) compared with liquid chromatography and bioassay methods for measurement of chloramphenicol.

A new enzyme immunoassay method (EMIT; Syva Co.) was compared with conventional high-performance liquid chromatography (HPLC) and agar-diffusion bioassay methods for measurement of chloramphenicol in human serum. Forty-nine serum samples were assayed by each of the three methods. Excellent correlation was observed between values by EMIT and by the two conventional methods (r = 0.986 and 0.961). Precision was acceptable (CV less than 5%) with EMIT. Assay of samples containing chloramphenicol glucuronide and chloramphenicol succinate demonstrated that EMIT recognizes only the biologically active (base) form of the drug. The capability to test serum samples as small as 0.2 mL, adaptation to widely available instrumentation, and provision of rapid results are principal advantages of the EMIT method for routine chloramphenicol measurements.