Subject(s)
Chemistry, Clinical/instrumentation , United States Food and Drug Administration/organization & administration , Equipment Safety , False Negative Reactions , Marketing of Health Services , Reagent Kits, Diagnostic , United States , United States Food and Drug Administration/legislation & jurisprudenceABSTRACT
The results of laboratory tests performed after fluorescein angiography may be erroneous because of interference by intravenous fluorescein. We investigated this potential interference in four adults at intervals of five minutes, three hours, six hours, and 12 hours after fluorescein injection. We used a panel of serum and urine chemistry tests on seven commonly used instruments. A significant change in the reported concentration of a serum or urine analyte was defined as a result beyond +/- 3 coefficients of variation of the preinjection baseline value for the test on a specific instrument. The determinations of creatinine, total protein, cortisol, digoxin, quinidine, and thyroxine in serum were affected by intravenous fluorescein. The urine tests were unaltered. The physician must be aware of the problem of interpreting clinical chemistry results after fluorescein angiography.
Subject(s)
Blood Chemical Analysis , Fluorescein Angiography , Fluoresceins/administration & dosage , Urine/analysis , Adult , Blood Proteins/analysis , Creatinine/blood , Female , Fluorescein , Humans , Injections, Intravenous , Male , Osmolar Concentration , Time FactorsABSTRACT
Accuracy, precision, and clinical laboratory utility of the TDX (Abbott Laboratories), Auto-ICS (Beckman Instruments, Inc.), COBAS-Bio (Roche Analytical Instruments, Inc.) with reagent kits (Syva), and EMIT (Syva) for gentamicin and tobramycin serum assay were assessed. TDX, COBAS-Bio, and EMIT analytical systems showed a proportional bias of less than 10% for recovery studies and a coefficient of variation less than 5% for within-run precision. The results of the recovery studies with the Auto-ICS showed a proportional bias of 25% with gentamicin and 16% with tobramycin. The within-run precision expressed as the coefficient of variation for the Auto-ICS was 6.7% for gentamicin and 8.6% for tobramycin. In comparisons involving gentamicin- and tobramycin-containing patient samples, the results with the TDX analytical system showed the best agreement with the COBAS-Bio. For the determination of these two antibiotics, the TDX analytical system provided the best overall accuracy and precision.
