Biomedical subjects

J D van Suijlen

Publications and source records attributed to J D van Suijlen.

5 recordsLinked to original sources

PubMed1999

Portable blood gas and electrolyte analyzer evaluated in a multiinstitutional study.

A recently introduced blood gas/electrolyte analyzer (SenDx 100((R)), renamed ABL70) intended for point-of-care, near-patient, or stat laboratory use was evaluated simultaneously in four different institutions and compared with three different laboratory bench analyzers with respect to imprecision, inaccuracy (assessed by tonometry), and patient-sample analyses. The analyzer is equipped with a sensor cassette and a reagent cartridge for 50, 100, or 200 analyses and 100 or more traditional quality-control measurements. One analysis requires 170 microL of whole blood and takes <90 s. Statistically, the instrument performed somewhat better (lower CVs) for PO2 and potassium and somewhat worse for pH, PCO2, and ionized calcium than the respective comparison analyzers. However, the overall performance (in terms of CV and accuracy) was satisfactory in terms of clinical (e.g., CLIA '88) goals in all institutions. The mean difference and the CV of that difference in some 400 patient-sample comparisons were as follows: 0.010 (+/- 0.002%) for pH, -0.65 mmHg (+/- 4%) for PCO2, -0.49 mmHg (+/- 6%) for Po2, 0.44 mmol/L (+/- 1.2%) for sodium, -0.013 mmol/L (+/- 2.9%) for potassium, -0.016 mmol/L (+/- 2.6%) for ionized calcium, and -0.016 L/L (+/- 7. 1%) for the hematocrit. Its acceptable analytical performance and ease of operation make the SenDx 100 suitable for the analysis of blood gases and electrolytes.

Blood Chemical Analysis↗

PubMed1993

The performance of the Chem-1 revisited: an evaluation after 3 years.

An evaluation of the Bayer-Technicon Chem-1 multitest analyzer is described over the period 1989-1992. Various aspects like daily use, running costs and quality assessment are discussed. The whole process regarding the performance, ranging from negative feelings in the first year to satisfaction in the third, is followed critically.

Chemistry Techniques, Analytical↗

PubMed1991

Calibration of Technicon Chem 1 multitest analysers.

Recently, two Technicon Chem 1 multitest clinical chemistry analysers were introduced after an evaluation in our laboratory. Calibration according to the instructions of the manufacturer resulted in significant differences between the assay results of the two Chem 1 analysers for twelve of twenty-two methods. To remove these differences we used an additional procedure based on the NCCLS EP-9P protocol for method comparison. Four reference methods were used as comparison methods. Our results indicate that, for three of these methods, the results on both Chem 1 analysers are biased in slope and intercept, and corrections of these parameters are necessary to produce results comparable to the reference method values. For the remaining eighteen assays, methods in routine use in our laboratory were used as comparison methods. In fifteen of eighteen assays, corrections of slope and (or) intercept were necessary to prevent changes in the cumulative average patient data produced by our laboratory. An adjustment of the slopes and intercepts, according to the multi-point calibration procedure presented here, resulted in significant differences between system-specific values measured in our laboratory and those assigned by the manufacturer for ten of thirteen methods. We conclude that the use of the multi-point calibration procedure presented in this article (based on calibration according to the instructions of the manufacturer and NCCLS EP-9P) greatly improves the intra-laboratory comparability and therefore should be part of multi-centre evaluations.

Autoanalysis↗

PubMed1990

A candidate reference method for coupled sodium-water determination in human serum.

A candidate reference method is described for coupled sodium-water determination based on ion-exchange sodium separation from the serum matrix followed by gravimetry as Na2SO4, and serum water determination by means of microwave evaporation. For sera with normal sodium and water contents, the mean relative standard deviation is 0.6% (0.8 mmol/l). Mean inaccuracy for the coupled sodium-water determination is -0.3% (0.4 mmol/l). The candidate reference method can be considered a reference method because the reference method value did not differ significantly from the definitive value, there is no known source for interferences or bias, and misinterpretation due to abnormal protein or lipid levels is excluded because serum sodium is determined on a plasma water basis. Sodium concentrations determined by the candidate reference method are used for comparing field methods with the candidate reference method. If the resulting regression equation is used in the calibration procedure, good correlation between all (in)direct field methods and the candidate reference method is ensured, and accurate results are produced. Results of proficiency testing show a good correlation between (in)direct field methods and the candidate reference method, because sera with approximately normal water contents are used.

Chemistry Techniques, Analytical↗

PubMed1990

Accuracy of serum ferritin determinations in tissue preparations and human serum.

Introduction of the NBSB 80/602 reference preparation for the calibration of ferritin immunoassays has reduced the inter-assay variability, and represents the first important step towards standardisation of ferritin immunoassays. However, our investigations show that comparison between assay results is still impossible, owing to differences in assay methodology and performance, differences in the specificities of the antibodies and antigens used and other possible interfering substances. We conclude that all kits detect mainly the more basic isoferritins in serum, and that all isoferritins (acidic, intermediate and basic) are systematically underestimated. Since we also showed possible immunological differences between reference or kit standards and serum ferritin, we conclude that the present kits have poor accuracy. To diminish inter-assay variability and to increase the accuracy of serum ferritin determinations, a method is needed that detects all basic, intermediate and acidic isoferritins and measures the true ferritin concentration in serum under normal and pathological circumstances. This reference method can be used to evaluate interference and systematic errors in routine methods. The introduction of a reference method, in combination with the NBSB 80/602 human liver reference preparation, is the second important step towards the accurate standardisation of ferritin immunoassays.

Antibodies↗