Performance characteristics of ELISAs for monitoring ketamine exposure.
BACKGROUND
Growing misuse of ketamine necessitates the development of high throughput testing approaches. Two commercial enzyme-linked immunosorbent assays (ELISA) for ketamine have recently become available and were adapted for this development.


METHODS
The newly available ketamine ELISA reagents were examined to better understand their cross-reacting, calibration and other performance characteristics. ELISA apparent analyte concentrations were also correlated against ketamine concentrations as determined by GC-MS to examine the relationship between these 2 parameters.


RESULTS
Both adapting ketamine as the targeted analyte, reagent from International Diagnostic Systems (IDS) also responded very significantly to the metabolites of ketamine (norketamine and dehydronorketamine), while the NEOGEN reagent responded very specifically to ketamine.


CONCLUSIONS
NEOGEN ELISA test data exhibit better correlation with the ketamine concentration as determined by GC-MS. It can be more reliably used as the preliminary test method in the 2-step approach now routinely adapted in workplace drug testing programs. Using 100 ng/ml ketamine as the GC-MS cutoff, the corresponding ELISA cutoff value is approximately 110-120 ng/ml. With significantly higher responses to ketamine metabolites, IDS reagent can detect specimens with much lower ketamine/metabolites concentrations and can better meet other testing requirements.
Huang
Mei-Han
MH
Department of Medical Technology, Fooyin University, 151 Ching-Hsueh Road, Ta-Liao Hsiang, Kaohsiung Hsien 831, Taiwan.
Wu
Meng-Yen
MY
Wu
Chih-Hung
CH
Tsai
Jin-Lian
JL
Lee
Hei-Hwa
HH
Liu
Ray H
RH
D000778:Anesthetics, Dissociative / Q000008:administration & dosage / Q000032:analysis*; D002138:Calibration; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods* / Q000592:standards; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007649:Ketamine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000032:analysis*; D012680:Sensitivity and Specificity; D015813:Substance Abuse Detection / Q000379:methods* / Q000592:standards
D000778:Anesthetics, Dissociative; D007649:Ketamine; C033419:norketamine