Band 47, Heft 6

Objectives Even though reliable glucose concentration measurements are essential in diagnosis and monitoring of diabetes mellitus, external quality assurance based on mandatory reference method values can only be conducted to a limited extent for measurements in whole blood. The reason is the lack of stabilized whole blood materials suitable for the application in glucose measurement devices used in near-patient testing. Methods Two patented whole blood stabilizers were tested using four commercially available near-patient testing devices and one patient self-testing device for plasma-referenced glucose measurements. Furthermore, a laboratory method for plasma-glucose measurements was included. Venous whole blood samples from 30 apparently healthy volunteers were used. Two whole blood samples (stabilizer A and B) per subject were kept at room temperature over the study period of seven days and aliquots were taken each day from the original sample for measurement on all devices. After venous puncture, left over whole blood from the collection system was used for immediate glucose measurements without stabilizer on the near-patient testing devices. Results Each investigated device gave stable results at least for one of the two stabilizers for a period of four days. Imprecision based on quality controls ranged between 1.7 and 4.8 % coefficient of variation for near-patient testing devices, but did not reflect observed variability in measurement results from stabilized and unstabilized whole blood in one device. In addition, a considerable deviation of 0.8 mmol/L was observed among the near-patient testing devices underlining the need for reference method values in external quality control. Conclusions Our study provides proof of concept that for each investigated device at least one stabilizer of glucose in whole blood shows a good performance for at least four days. Therefore, these stabilizers appear to be suitable candidate materials for external quality assessment of near-patient testing devices.

Objectives IL-6 is an inflammatory marker and urea nitrogen (UREA) is a common indicator of glomerular filtration function. Their combined detection has predictive value for the severity of neonatal pneumonia. Methods We performed a cross-sectional analysis of the clinical and laboratory data, collected from 105 neonatal patients (including 76 mild to moderate pneumonia patients and 29 severe pneumonia patients). Results Mann–Whitney U-test showed serum IL-6 and UREA levels were significantly increased in severe pneumonia, compared with that in mild to moderate pneumonia (p<0.05). Correlation analysis showed the severity of neonatal pneumonia was positively correlated with serum IL-6 (r=0.284, p<0.05) and UREA (r=0.303, p<0.05) levels. Multivariate logistic regression analysis showed the increased levels of IL-6 (OR=1.002, 95 % CI 1.001–1.004) and UREA (OR=1.420, 95 % CI 1.046–1.926) were independent risk factors for the severity of neonatal pneumonia. ROC curve analysis showed that the predictive value of combined detection of serum IL-6 and UREA in the severity of neonatal pneumonia was better than that of either detection alone (area under curve [AUC] = 0.809, 95 % CI 0.711–0.894, p<0.001). Conclusions Combined detection of IL-6 and UREA had a good predictive value for evaluating the severity of neonatal pneumonia.

Objectives The cellular composition of body fluids (BF) provides insight into disease pathology and is an important diagnostic parameter. The well-established Sysmex XN haematology analyser (XN) offers automated BF analysis and is in routine use in many laboratories. In this study the performance of the new Sysmex XR analyser (XR) in testing BF is compared to the XN. Methods Cerebrospinal, pleural, peritoneal, and synovial fluids, as well as bronchoalveolar lavage (BAL) samples, were processed in BF mode on both analysers. Standard statistical methods were used to evaluate the performance of XR compared to the reference XN. Results Cell counts were generated from a total of 356 measurements from 307 patient BF samples. After application of exclusion criteria, 86 cerebrospinal, 77 peritoneal, 78 pleural, and 89 synovial fluid sample pairs were compared. An excellent correlation coefficient (r) between the two analysers was observed for all diagnostic parameters; WBC-BF: 0.996, RBC-BF: 0.974, TC-BF: 0.995, MN#: 0.994, MN%: 0.830, PMN#: 0.985 and PMN%: 0.835. The research parameters also performed equally well (r values of 0.900–0.994). The performance of diluted and undiluted samples was equally good. Similar results for diagnostic and research parameters were obtained from 62 BAL samples (r values of 0.899–0.992). Conclusions This study demonstrates that the automated BF counts on the new Sysmex XR analyser are equivalent to that of the XN for all BF types analysed.

Objectives The aim is to evaluate the effect of viral inactivation methods on the quality and quantity of compounds in dried blood spots (DBS). Methods Three effective and common inactivation methods were selected via the literature search, including: heating at 56 °C for 30 min, irradiation with UVC for 30 min, and surface wetting with 70 % ethanol. The concentration and clinical predicting significance of hormones, amino acids, and acylcarnitines from DBS were assessed, and the quality and quantity of extracted deoxyribonucleic acid (DNA) from DBS were evaluated. Results Compared to control, we found that there was no significant difference on hormones concentration in the DBS treated by heating at 56 °C for 30 min (thyroid stimulating hormone p=0.36, 17-hydroxyprogesterone p=0.52). And heating at 56 °C for 30 min had a minimal changed coefficient of variation on the concentration of amino acids and acylcarnitines. All three inactivation methods slightly changed the yield of DNA extraction, but did not affect the quality of the DNA. Importantly, the three inactivation methods wouldn’t change the clinical predicting significance of above-compounds mostly, especially heating at 56 °C for 30 min. Conclusions Considering the minimal effect on the quality and quantity of various compounds, the contaminated DBS could be pretreated by the three inactivation methods, as temporary emergency inactivation methods, especially heating at 56 °C for 30 min.

Objectives The ‘Thomas plot’ is a very helpful diagnostic tool for evaluation, monitoring and therapy of the iron status and on the hemoglobinization of the reticulocytes of patients. In 2021 Roche Diagnostics launched a second generation assay for determination of the soluble transferrin receptor (sTfR). Here we compare the old and the new assay for sTfR and analyze the consequences for the ‘Thomas plot’. Methods Measurement of sTfR, ferritin and CRP were done using a Cobas8000 system. Hemoglobin content of reticulocytes (Ret-He) was determined using a Sysmex XN9000 system. Results The second generation of sTfR assay showed consistently lower sTfR values compared to the first generation, which would result in a left shift of the ‘Thomas plot’ and may lead to false diagnosis of patients using the original cut-offs. Fifteen thousand five hundred ninty two data sets for ‘Thomas plot’ from 2016 to 2021 were retrospectively analyzed to estimate how many patients in our hospital would be affected. In result around 5 % of all ‘Thomas plots’ would be affected by the lower sTfR values of the second generation assays. Conclusions Due to the lower sTfR values measured with the second generation assay new cut-offs for the Ferritin-Index (sTfR/lg Ferritin) should be used in order to correctly diagnose the iron status of patients.