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Optimization and validation of CEDIA drugs of abuse immunoassay tests in serum on Hitachi 912.
Forensic Sci Int. 2011 Oct 10; 212(1-3):252-5.FS

Abstract

Due to sensitive limits of detection of chromatographic methods and low limit values regarding the screening of drugs under the terms of impairment in safe driving (§ 24a StVG, Street Traffic Law in Germany), preliminary immunoassay (IA) tests should be able to detect also low concentrations of legal and illegal drugs in serum in forensic cases. False-negatives should be avoided, the rate of false-positive samples should be low due to cost and time. An optimization of IA cutoff values and a validation of the assay is required for each laboratory. In a retrospective study results for serum samples containing amphetamine, methylenedioxy derivatives, cannabinoids, benzodiazepines, cocaine (metabolites), methadone and opiates obtained with CEDIA drugs of abuse reagents on a Hitachi 912 autoanalyzer were compared with quantitative results of chromatographic methods (gas or liquid chromatography coupled with mass spectrometry (GC/MS or LC/MS)). Firstly sensitivity, specificity, positive and negative predictive values and overall misclassification rates were evaluated by contingency tables and compared to ROC-analyses and Youden-Indices. Secondly ideal cutoffs were statistically calculated on the basis of sensitivity and specificity as decisive statistical criteria with focus on a high sensitivity (low rates of false-negatives), i.e. using the Youden-Index. Immunoassay (IA) and confirmatory results were available for 3014 blood samples. Sensitivity was 90% or more for nearly all analytes: amphetamines (IA cutoff 9.5 ng/ml), methylenedioxy derivatives (IA cutoff 5.5 ng/ml), cannabinoids (IA cutoff 14.5 ng/ml), benzodiazepines (IA cutoff >0 ng/ml). Test of opiates showed a sensitivity of 86% for a IA cutoff value of >0 ng/ml. Values for specificity ranged between 33% (methadone, IA cutoff 10 ng/ml) and 90% (cocaine, IA cutoff 20 ng/ml). Lower cutoff values as recommended by ROC analyses were chosen for most tests to decrease the rate of false-negatives. Analyses enabled the definition of cutoff values with good values for sensitivity. Small rates of false-positives can be accepted in forensic cases.

Authors+Show Affiliations

Institute of Forensic Medicine, Rheinische Friedrich-Wilhelms University, Stiftsplatz 12, D-53111 Bonn, Germany.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Validation Study

Language

eng

PubMed ID

21775079

Citation

Kirschbaum, Katrin M., et al. "Optimization and Validation of CEDIA Drugs of Abuse Immunoassay Tests in Serum On Hitachi 912." Forensic Science International, vol. 212, no. 1-3, 2011, pp. 252-5.
Kirschbaum KM, Musshoff F, Schmithausen R, et al. Optimization and validation of CEDIA drugs of abuse immunoassay tests in serum on Hitachi 912. Forensic Sci Int. 2011;212(1-3):252-5.
Kirschbaum, K. M., Musshoff, F., Schmithausen, R., Stockhausen, S., & Madea, B. (2011). Optimization and validation of CEDIA drugs of abuse immunoassay tests in serum on Hitachi 912. Forensic Science International, 212(1-3), 252-5. https://doi.org/10.1016/j.forsciint.2011.06.029
Kirschbaum KM, et al. Optimization and Validation of CEDIA Drugs of Abuse Immunoassay Tests in Serum On Hitachi 912. Forensic Sci Int. 2011 Oct 10;212(1-3):252-5. PubMed PMID: 21775079.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Optimization and validation of CEDIA drugs of abuse immunoassay tests in serum on Hitachi 912. AU - Kirschbaum,Katrin M, AU - Musshoff,Frank, AU - Schmithausen,Ricarda, AU - Stockhausen,Sarah, AU - Madea,Burkhard, Y1 - 2011/07/20/ PY - 2010/11/13/received PY - 2011/06/20/revised PY - 2011/06/27/accepted PY - 2011/7/22/entrez PY - 2011/7/22/pubmed PY - 2012/2/3/medline SP - 252 EP - 5 JF - Forensic science international JO - Forensic Sci. Int. VL - 212 IS - 1-3 N2 - Due to sensitive limits of detection of chromatographic methods and low limit values regarding the screening of drugs under the terms of impairment in safe driving (§ 24a StVG, Street Traffic Law in Germany), preliminary immunoassay (IA) tests should be able to detect also low concentrations of legal and illegal drugs in serum in forensic cases. False-negatives should be avoided, the rate of false-positive samples should be low due to cost and time. An optimization of IA cutoff values and a validation of the assay is required for each laboratory. In a retrospective study results for serum samples containing amphetamine, methylenedioxy derivatives, cannabinoids, benzodiazepines, cocaine (metabolites), methadone and opiates obtained with CEDIA drugs of abuse reagents on a Hitachi 912 autoanalyzer were compared with quantitative results of chromatographic methods (gas or liquid chromatography coupled with mass spectrometry (GC/MS or LC/MS)). Firstly sensitivity, specificity, positive and negative predictive values and overall misclassification rates were evaluated by contingency tables and compared to ROC-analyses and Youden-Indices. Secondly ideal cutoffs were statistically calculated on the basis of sensitivity and specificity as decisive statistical criteria with focus on a high sensitivity (low rates of false-negatives), i.e. using the Youden-Index. Immunoassay (IA) and confirmatory results were available for 3014 blood samples. Sensitivity was 90% or more for nearly all analytes: amphetamines (IA cutoff 9.5 ng/ml), methylenedioxy derivatives (IA cutoff 5.5 ng/ml), cannabinoids (IA cutoff 14.5 ng/ml), benzodiazepines (IA cutoff >0 ng/ml). Test of opiates showed a sensitivity of 86% for a IA cutoff value of >0 ng/ml. Values for specificity ranged between 33% (methadone, IA cutoff 10 ng/ml) and 90% (cocaine, IA cutoff 20 ng/ml). Lower cutoff values as recommended by ROC analyses were chosen for most tests to decrease the rate of false-negatives. Analyses enabled the definition of cutoff values with good values for sensitivity. Small rates of false-positives can be accepted in forensic cases. SN - 1872-6283 UR - https://www.unboundmedicine.com/medline/citation/21775079/Optimization_and_validation_of_CEDIA_drugs_of_abuse_immunoassay_tests_in_serum_on_Hitachi_912_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0379-0738(11)00314-8 DB - PRIME DP - Unbound Medicine ER -