Results of the multicenter evaluation of the CEDIA Theophylline assay.

We report on the results of the multicenter evaluation of the CEDIA Theophylline assay on Boehringer Mannheim/Hitachi analyzers in 15 clinical laboratories in Europe and U.S.A. Main items of investigation were imprecision, recovery of control sera, interlaboratory survey and method comparisons using patient samples. Imprecision was found to be comparable to other routine methods. An advantage of the CEDIA assay can be seen in the good interlaboratory transferability of results. The new test has been shown to measure very accurately particularly by comparison with HPLC procedures revealing highly correspondent results. The reagent can be used up to one month using multiple recalibration. Due to its high practicability and reliability the CEDIA Theophylline assay can be recommended as a very suitable routine method for therapeutic drug monitoring on random access analyzers like Boehringer Mannheim/Hitachi analysis systems.

Results of the multicenter evaluation of the CEDIA Phenytoin assay.

Thirteen clinical evaluation sites in Europe and U.S.A. investigated the CEDIA Phenytoin assay on Boehringer Mannheim/Hitachi analyzers with respect to imprecision, recovery of control sera, interlaboratory survey, linearity and method comparisons using patient samples. The linear dose-response relationship up to 40 micrograms/mL was confirmed by all participants. Imprecision at therapeutic analyte concentrations equalled that of other routine methods. Recovery of controls was found in a +/- 6% range for target values assigned by the CEDIA assay. The good interlaboratory transferability of the CEDIA assay was confirmed with control material and human samples. The reconstituted reagent can be used up to one month using weekly recalibration. In method comparison studies good correlations to other routine methods were obtained. Results in analyte-free human sera did not deviate systematically from the zero-point. Thus, the accuracy in patient sera has been shown for the CEDIA Phenytoin assay.

Results of the multicenter evaluation of the CEDIA Phenobarbital assay.

The CEDIA Phenobarbital assay has been evaluated in twelve clinical laboratories in Europe and U.S.A. on Boehringer Mannheim/Hitachi analysis systems. The evaluation focused on the analysis of imprecision and accuracy. Within-run and between-day coefficients of variations of the new assay were comparable to those of established routine methods. As demonstrated in an interlaboratory survey study with controls and human sera, results obtained in different laboratories showed a good agreement. The CEDIA Phenobarbital assay measured very accurately, as particularly confirmed by comparison with HPLC. It can be recommended as a reliable and practicable test for monitoring of phenobarbital on Boehringer Mannheim/Hitachi analyzers used in routine clinical chemistry.

Investigation of the performance of the ES 600 Enzymun-Test system. A multicentre study.

The ES 600 sample-selective multibatch analyser was subjected to a multicentre evaluation in six laboratories in accordance with ECCLS guide-lines. During the 3-month trial, five Enzymun-Test diagnostics (T4, TBG, Digoxin, CEA and TSH)1) were measured at 25 degrees C. The study yielded the following results: 1. The within-series and between-series precision were very good, with mean CV's of approx. 3% and 7% respectively. 2. Recovery of the target values for three control sera was in the range +/- 5%. 3. A trend in measurements did not occur in any of the methods investigated (for series of over 240 determinations). 4. Comparison of the results with those obtained on the ES 22 Enzymun-Test system showed good agreement. 5. Within the measuring range defined by the standards, no deviations could be ascertained upon dilution of the samples. 6. Total carry-over in the instrument was below 0.05%. From studies with instruments from the first production series, it became evident that modifications were necessary to improve the reliability. A follow-up measuring programme confirmed a clear improvement in reliability and a reduction in the imprecision, particularly for results from series to series.