ABSTRACT
Errors made during the sample preparative process contribute significantly to the total analytical error of immunoassays. Reduction in the magnitude of these errors have been made by improvements in the manualfluid handling systems and mechanization of the individual steps in the process. The mechanization has been stimulated by developments in both computing hardware and software. A laboratory's workflow and workload will indicate the degree of mechanization required.
ABSTRACT
Reference intervals for creatine kinase assayed at 37 degrees C using N-acetyl cysteine-activated methods have been determined on data obtained from 10 laboratories throughout Australia. The pooled distributions for males and females are skewed towards higher values and cannot be transformed to Gaussian distributions. The reference interval for females was calculated to be 34 to 180 U/l and for males it was 46 to 300 U/l. However, if creatine kinase is to be used in the diagnosis of myocardial infarction, the upper limit of the reference interval for males is considered to be too high. It is concluded that for males, the upper limit may need to be determined on specific populations such as hospital inpatients.
Subject(s)
Creatine Kinase/blood , Australia , Data Interpretation, Statistical , Female , Humans , Male , Multicenter Studies as Topic , Numerical Analysis, Computer-Assisted , Reference Values , Sex FactorsABSTRACT
Two surveys of the proficiency of performance of serum ferritin estimation in Australia have been conducted, one in 1978 and one in 1979. The majority of participants in both surveys used assay kits supplied by Clinical Assays, Roche Diagnostics and Ramco. The first survey showed a median intrabatch variation 9% and median interbatch variation of 17%. The overall assay variation had a median level of 22%. Assays by the various kits gave values which were not significantly different for each specimen (including purified liver and spleen ferritin solutions). The second survey showed an improvement in the overall precision of the participants with a median coefficient of variation of 15%. Contrary to the first survey, significant differences were evident between the results in 4 of the 5 specimens assayed. Some participants returned results for the high ferritin serum that differed substantially depending on the dilution of the sample used. The surveys showed a need for improvement in the assay performance of some participants, the need for ferritin levels to be assayed at least in two dilutions, and the need for standardization of assays, reference ranges and reporting units. Recommendation are made on all these points.
Subject(s)
Ferritins/blood , Radioimmunoassay/methods , HumansABSTRACT
The EMIT (Enzyme Multiplied Immunoassay Technique) for serum gentamicin determination was evaluated by a standard procedure. The precision, accuracy, and specificity were assessed and proved satisfactory. Comparison with a bioassay was done, and results for patient samples showed a correlation coefficient of 0.95 between the two methods. Advantages of the enzyme immunoassay system were the provision of results within 15 min of receipt of blood in the laboratory, a requirement of minimal technical expertise, and an applicability to both large and small workloads. The EMIT proved during evaluation to be a practical alternative to current bioassays for the determination of serum gentamicin concentrations.
Subject(s)
Gentamicins/blood , Immunoenzyme Techniques , Carbenicillin/blood , Drug Interactions , Drug Stability , Humans , Ticarcillin/bloodABSTRACT
The Hyland and Behring laser nephelometer systems for assay of specific proteins are described. Immunoglobulin G was measured to assess the overall performance of the two systems. Intra-batch precision figures were comparable to those for the radial immunodiffusion method run routinely in our laboratory. There was no significant interference from turbid or lipemic specimens. Accuracy, ease of instrument operation, standard curve stability, linearity, and accessory equipment are discussed. Immunoglobulin G is measured rapidly, accurately, and precisely by either system.
