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ABSTRACT 2
ABSTRACT 1
Quality of blood samples collected at home does not affect clinical decision making for the administration of systemic cancer treatment.
Interference of anti-streptavidin antibodies in immunoassays: a very rare phenomenon or a more common finding? Verougstraete N, Berth M, Delanghe J, Callewaert N, et al. Clinical Chemistry and Laboratory Medicine, 2020, 58(10), 1673-1680
INTRODUCTION Anti-streptavidin antibodies (ASA) may cause analytical interference on certain immunoassay platforms. Streptavidin is purified from the non-pathogenic Streptomyces avidinii soil bacterium. In contrast to interference with biotin, ASA interference is supposed to be much rarer. In-depth studies on this topic are lacking. Therefore, we carried out an analysis toward the prevalence and the possible underlying cause of this interference.
MATERIALS/METHODS Anti-streptavidin (AS)-immunoglobulin G (IgG) and AS-IgM concentrations were determined on multiple samples from two patients with ASA interference and on 500 random samples. On a subset of 100 samples, thyroid-stimulating hormone (TSH) was measured on a Cobas analyzer before and after performing a neutralization protocol which removes ASA. The relationship between the ratio of TSH after neutralization/TSH before neutralization and the ASA concentration was evaluated. Subsequently, an extract of S. avidinii colonies was analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting.
RESULTS A positive correlation between AS-IgM concentrations and TSH ratio was obtained. Eight samples out of 500 exceeded the calculated AS-IgM cut-off value. In comparison to the AS-IgM concentrations in the population, titers from the two described cases clearly stood out. The isolated cases represent the end of a broader spectrum as there is a continuum of AS-IgM reactivity in the general population. We could not observe any differences in the immunoblot patterns between the cases and controls, which may indicate the general presence of ASA in the population.
CONCLUSION Interference due to ASA is more prevalent than initially thought and is caused by IgM antibodies.
Cool L, Callewaert N, Pottel H, Van Eygen K, et al. Scandinavian Journal of Clinical and Laboratory Investigation, 2020, 80(3), 215-221
OBJECTIVE The aim of this exploratory clinical study was to evaluate whether the preanalytical quality of blood samples subjected to delayed centrifugation and transport – as a result of home-sampling – is affected in a way it alters the clinical decision-making for oncological home-hospitalization.
MATERIALS/METHODS Forty-nine patients with cancer donated two additional blood samples during their ambulatory hospital visit. Fifteen blood analytes were compared between routine blood samples and samples that were subjected to transport and delayed centrifugation in order to mimic a locally implemented model for oncological home-hospitalisation. Deviations were analysed by means of Deming regression. For those analytes showing statistically significant intercepts and/or slopes, the mean deviations were compared to the desirable analytical bias; and the intra-individual differences were compared with the limits for clinical decision-making.
RESULTS Statistically significant intercepts and/or slopes were observed for haematocrit (HCT), mean cellular volume (MCV), platelets count (PLT) and C-reactive protein (CRP). Differences exceeding the allowable margins of desirable analytical bias were observed for HCT and MCV. Risk of different clinical decision-making couldn’t be observed for any of the analytes showing statistically significant differences.
CONCLUSION These results demonstrate that home-collection of blood samples, transported at room temperature and centrifuged within a mean time of five hours after sampling, has no effect on clinical decision-making with regards to systemic cancer therapy. However, attention should be paid to the potential occurrence of haemolysis during the preanalytical phase, which can negatively influence haemolysis-dependent variables.
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