Scandinavian Journal of Clinical & Laboratory Investigation最新文献

The aim of the present study was to extend the creatinine-based Lund-Malmö GFR equation for use with rescaled cystatin C (r-LMR_Cys) and validate it against measured GFR (mGFR) in the EKFC cystatin C cohort of children (n = 2,293) and adults (n = 7,727). Rescaling was obtained by dividing each biomarker by a Q-value, representing the population-specific median biomarker level among healthy individuals. Validation included median bias/precision/accuracy (percent estimates within ±30% of mGFR, P₃₀). Performance was compared with the EKFC-equation (EKFC_Cys), the CAPA cystatin C equation, the corresponding equations based on rescaled creatinine (r-LMR_Cr and EKFC_Cr) and the arithmetic mean of r-LMR_Cr and CAPA (r-LMR_Cr+CAPA), r-LMR_Cr and r-LMR_Cys (r-LMR_Mean), and EKFC_Cr and EKFC_Cys (EKFC_Mean). The overall P₃₀ of r-LMR_Cys in adults was 86.2% (95% CI 85.4%-86.9%), which was 6.6 percentage points (pp; 95% CI 5.8-7.4 pp) higher than for CAPA and similar to r-LMR_Cr (P₃₀ 87.4%, 95% CI 86.6%-88.1%). r-LMR_Cys and EKFC_Cys exhibited similar performance both overall and across subgroups of age, sex, GFR and BMI and in children. All three arithmetic mean equations had similar P₃₀-accuracy and generally performed better than the corresponding single-marker equations. Our results show that the Lund-Malmö GFR equation can be adapted for use with rescaled cystatin C with performance that is similar to the best-performing equations based on rescaled creatinine. The generality of the applied biomarker rescaling principle implies that the future demand for population- and biomarker-specific GFR estimating equations can be expected to decrease substantially.

Haemolysis occurring during cardiac surgery with cardiopulmonary bypass (CPB) is assumed to be a risk factor for postoperative acute kidney injury (AKI). Plasma alpha-1 microglobulin (A1M) may have a protective role as haem scavenger. The aim of this study was to evaluate the association between AKI and the degree of haemolysis and the course of A1M concentrations during cardiac surgery, respectively. We analysed plasma concentrations of free haemoglobin (pfHb) and A1M in 25 patients undergoing cardiac surgery: before CPB; during CPB in 15 min intervals; after CPB; and at four additional time points until 24 h after surgery. Markers of kidney function were followed until 4 days after surgery. Detection of AKI was based on the KDIGO (Kidney Disease, Improving Global Outcome) criteria. The plasma concentration of free haemoglobin during CPB was found to be significantly higher in patients with postoperative AKI at 60 min after start of CPB [mean 1379 µg/mL (95% CI: 1037-1721)]; compared to [820 µg/mL (622-1018)]; p = 0.034, in patients without AKI, and at one hour post-CPB [2600 µg/mL (969-4230)] vs [1037 µg/mL (722-1353)]; p = 0.044]. There was no significant difference found for pA1M levels between the groups with and without postoperative AKI development. Haemolysis during cardiac surgery with CPB increases the risk of postoperative AKI. Levels of pA1M did not differ for patients who developed postoperative AKI compared with those who did not. The data did not allow conclusions regarding the hypothesis that pA1M has a reno-protective effect.

Cerebrospinal fluid (CSF) is routinely investigated to diagnose subarachnoid haemorrhage (SAH) in cases with unclear neuroimaging findings. Using spectrophotometry, the levels of bilirubin and oxyhaemoglobin are analysed. This study investigates the stability for bilirubin and oxyhaemoglobin in CSF samples for up to 3 weeks measured with a spectrophotometer. The absorbances corresponding to bilirubin (455 nm) and oxyhaemoglobin (415 nm) remained fairly stable for up to 3 weeks when samples were stored at +4 °C with light protection. There was a statistically significant trend of decreased absorbance for both oxyhaemoglobin and bilirubin already after exposure to light within 120 min from sampling. It is therefore advisable to protect CSF from light until spectrophotometric analysis.

Background: Inborn Errors of Immunity (IEIs) are genetic diseases resulting from harmful genetic variations that hinder the proper functioning of the immune system. The broad range of IEIs involves multiple systems, presenting characteristics similar to allergies, autoimmune or inflammatory diseases, and malignancies. Given this complexity, there is an urgent need for a precise multi-parametric molecular diagnostic approach.

Objective: In this work, we demonstrated the effectiveness of accurate diagnosis by flow cytometry in patients with IEI by comparing genotype analysis with the expression levels of particular proteins and signaling activities.

Methods: We examined the expression levels or signaling activities of 28 cell surface and intracellular proteins using flow cytometry in a cohort of 352 patients and 189 healthy controls, in conjunction with genotype analysis for comparison. Results: We identified alterations in protein expression in 60 individuals, among them, 55 exhibited the presence of an underlying pathogenic mutation. Complete loss of protein expression was observed in seven patients, constituting 2% of the total, while reduced protein expression was noted in 35 patients (9%). Notably, despite mutations in the relevant genes, protein expression levels were normal in five patients (2%), in all investigated patients. 37% of patients had elevated signaling activity, and 17% were suggestive of a particular IEI diagnosis following protein expression analysis.

Conclusion: The correspondence between flow cytometry-based protein analyses and genotype facilitates a prompt diagnosis, providing patients with swift access to therapeutic options.

Introduction: Verification and validation of analytical methods are crucial aspects of quality assurance in a laboratory. This study aimed to develop a risk analysis and assessment tool to streamline the process of identifying so-called 'sentinel' tests.

Materials and methods: The Roche Cobas 8000 systems were evaluated to analyze 83 serum analytes, including routine chemistry, immunoassays, and therapeutic drugs. A failure mode and effects analysis were conducted to produce an analytic risk rating. This was achieved by multiplying the scores for Sigma metrics, the score for potential damage extent, and the score for environmental factors. Each test was assigned a typical risk priority number (RPN). Tests with an RPN of ≤9 were rated as low risk and ranked as 'B'. Tests with an RPN of >10 were considered high risk and graded as 'A'.

Results: Regarding the Cobas C701/ISE, 17 of 54 methods were rated as 'A' and subject to a systematic method review process. A total of 37 methods were assigned a rank of 'B' and hence were eligible for a selective verification process. Concerning the Cobas E801, 10 out of 29 methods were classified as 'A' and, therefore, require a systematic verification process. A further nineteen methods were assigned a rank of 'B' and hence eligible for a select verification.

Conclusions: This study demonstrated the high effectiveness of the risk analysis and assessment model developed to identify sentinel tests in the lean management of the verification/validation process.

Saliva samples offer the possibility to obtain stress-free non-invasive samples, also for home-testing, especially useful when blood collection is either undesirable or difficult. The aim of this work was to develop an LC-MS/MS method to determine clinically relevant steroid hormones cortisol, cortisone, 11-deoxycortisol, 21-deoxycortisol, 17OH-progesterone, aldosterone, corticosterone, deoxycorticosterone, testosterone, androstenedione, DHEAS, DHEA, 17OH-pregnenolone, betamethasone and dexamethasone. A special effort was made to adapt the method to neonatal population with respect to choice of saliva as matrix, low sample volumes, selection of analytes and multiplexing. Validation included selectivity, interferences, matrix effects, lower and upper limit of quantification, linearity of calibration, dilution of samples, trueness, within-run and total analytical repeatability, robustness, carry-over, stability and recovery from sample collection swab. Ten microliters were acceptable but 50 µL preferable sample volume, except for 21-deoxycortisol. Cortisol, cortisone, aldosterone, 11-deoxycortisol, deoxycorticosterone, dexamethasone, betamethasone, 17OH-pregnenolone and DHEAS could be determined in as little as 2-5µL saliva. Total analytical variation was <15%, except for 17OH-progesterone, deoxycorticosterone, 17OH-pregnenolone, 21-deoxycortisol, androstenedione, DHEA and betamethasone, that could only be determined semi-quantitatively or qualitatively. The minimum turnaround time was 3-4 h. Recovery from the best performing sample collection swab SalivaBio ranged from 83 to 127%. Aldosterone, cortisone and DHEA were more stable in saliva compared to serum when stored at ambient temperature for one week. Corticosterone and 17OH-progesterone needed immediate freezing. The non-invasiveness, small saliva volume requirement, on-swab stability and analytical performance make the method relevant for both research and diagnostics, above all in the setting of neonatal intensive care unit.

HbA_1c plays an important role in the diagnosis and treatment of diabetes and is a valuable biomarker for evaluating glycemic control and predicting the risk of vascular complications. The study aimed to determine the biological variation (BV) for HbA_1c and thereby contribute to analytical performance specifications, reference change values, and index of individuality. Fasting venous whole blood samples were collected from 38 presumably healthy subjects (20 females, 18 males) once a week for ten weeks, and analyzed in duplicate using the Roche Cobas c501 analyzer. BioVar, an online R-based biological variation analysis tool, was used for the statistical analysis. BV values were obtained by analysis of variance (ANOVA) after outlier detection, normality tests, steady-state, and homogeneity checks. The within-subject biological variation for HbA_1c was 2.9%, and the between-subject biological variation was 7.9%. The index of the individuality of HbA_1c was 0.37. Derived desirable analytical goals for imprecision, bias, total allowable error, and maximum expanded allowable measurement uncertainty were 1.4%, 1.8%, 4.2%, and 2.9% respectively. The reference change value is more appropriate for interpreting HbA1c results than a population-based reference interval.

Direct oral anticoagulants (DOAC) are increasingly common, with bleeding events associated with elevated plasma concentrations. Rotational thromboelastometry (ROTEM), a point-of-care tool for assessing secondary hemostasis, has demonstrated a correlation with increasing concentrations of DOAC. However, previous studies have only partially explored this relationship. The primary aim in the current study was to investigate the impact of increasing rivaroxaban concentrations on clotting time (CT) in the EXTEM assay. The secondary aims were to investigate the impact of increasing rivaroxaban concentrations on clot formation time (CFT) and α-angle (AA) and to investigate the impact of increasing concentrations of dabigatran and apixaban on CT, CFT and AA. Blood from 12 healthy volunteers was spiked to anticipated concentrations of rivaroxaban, dabigatran and apixaban at 0, 50, 100, 200, 500 and 1000 µg/L each. Blood with these varying concentrations was analyzed in four different ROTEM assays and CT, CFT and AA were extracted. CT increased linearly with increasing concentrations of all three DOACs. Rivaroxaban and dabigatran spiked blood showed an increase in CT-EXTEM for the 200-1000µg/L concentrations, compared to baseline, and apixaban for the 500-1000 µg/L concentrations. CFT and AA were affected only in supratherapeutic concentrations for all tested DOACs and primarily in the INTEM assay. Among the tested DOACs, apixaban demonstrated the least impact on CT across all assays. In conclusion, ROTEM-derived CT measurements can serve as surrogate markers for DOAC concentrations.

Venous blood is considered an acceptable alternative to arterial blood for assessment of metabolic acid-base disorders. Also, venous sampling using lithium-heparin (Li-Hep) tubes is advantageous to arterial sampling using PICO syringes, the risk of complications being lower. Usage of partly filled tubes without firm knowledge about the clinical consequences is, however, a pre-analytic consideration. The study evaluated primary acid-base parameters (pH, standardized hydrogen carbonate (HCO₃), standardized base excess (SBE), lactate) and co-determined parameters in venous blood stored at room temperature up to 60 min in Li-Hep tubes vs. venous blood in PICO syringes analyzed immediately. Also, 50% filled tubes stored up to 30 min were compared to filled tubes analyzed immediately. Significant differences were generally observed. Stability was parameter and time dependent (filled tubes: 30 min: pH, (preferably 15 min for optimal stability), SBE, potassium and lactate, 60 min: HCO₃, hemoglobin, methemoglobin (MetHb), carbon monoxide hemoglobin (COHb), sodium, chloride, glucose and creatinine; 50% filled tubes: 15 min: lactate, 30 min: HCO₃, hemoglobin, MetHb, COHb, potassium, sodium, chloride, glucose and creatinine). In conclusion, storage in filled Li-Hep tubes for 30 min generates comparable results to blood in PICO syringes for all parameters, except pCO₂, pO₂ and sO₂. Storage in 50% filled Li-Hep tubes is not acceptable for pH, pCO₂, pO₂, sO₂ and SBE, and lactate is only stable for 15 min.