RESUMO
The anti-double-stranded (ds)DNA antibody test is an integral part of diagnosing systemic lupus erythematosus when the entry criterion is satisfied. We investigated the sensitivity of the BioPlex 2200 instrument compared with the serological gold standard and other tests and clinical information. The results showed an unacceptable sensitivity for this method. Laboratories should be cognizant of this shortcoming when selecting this platform for dsDNA antibody testing.
RESUMO
BACKGROUND: Carbamazepine is an effective drug for treating seizures and trigeminal neuralgia. Therapeutic drug monitoring of free carbamazepine in serum can be useful in situations that drug--protein binding is altered to guide regimen adjustment and to aid in the diagnosis of clinical toxicity. METHODS: Separation of the nonprotein bound carbamazepine was achieved via ultrafiltration through a molecular weight cut-off filter. A method for free carbamazepine measurement was developed on the automated cobas chemistry analyzers (Roche Diagnostics) by modifying the Carbamazepine Gen 4 assay (Roche Diagnostics). Assay performance characteristics were established including precision, accuracy, reportable range, analytical specificity, and stability. RESULTS: The intra- and inter-assay imprecision was 0%-1.4% and 2.4%-5.1%, respectively. The lower limit of quantitation was 0.3 µg/mL, and the assay was linear up to 10.0 µg/mL. A spike recovery study, using reference standard material, showed recovery was 93.5%--101.3% across the analytical measurement range. Method comparison with a reference laboratory method demonstrated equivalent performance with a slope of 1.01, intercept of 0.09, and correlation coefficient of 0.9948. CONCLUSION: This assay provides a simple and accurate method for monitoring free carbamazepine with a fast turnaround time.