Scandinavian Journal of Clinical & Laboratory Investigation最新文献

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.

A low eGFR_{cystatin C}/eGFR_creatinine-ratio is characteristic of a group of serious kidney disorders called 'Selective Glomerular Hypofiltration Syndromes'. This study examines if such a low ratio can also be used to evaluate the risk for women with hypertensive disorders in pregnancy to develop severe maternal morbidity. All women discharged from the perinatal ward at the Skåne University Hospital in Lund during the period of 1-9-2016 to 31-8-2017 under one of the diagnoses within hypertensive disorders in pregnancy were considered for inclusion in the study. After delivery and discharge from the hospital, records from included patients were reviewed and all registered measures of renal function were analysed. An eGFR_{cystatin C}/eGFR_creatinine-ratio ≤0.60 in a sample drawn not earlier than three days before delivery was considered as defining a high risk for severe maternal morbidity. A strong association (p-value: 0.035) between severe maternal morbidity and an eGFR_{cystatin C}/eGFR_creatinine-ratio ≤0.60 was found in a subgroup of 32 women diagnosed with 'preeclampsia with severe features'. A total of 69 women were included in the study. Fifty were defined as high-risk and seventeen of them (34%) developed severe maternal morbidity. Among the nineteen women defined as low-risk only two (10.5%) developed severe maternal morbidity (p-value: 0.051). A low eGFR_{cystatin C}/eGFR_creatinine-ratio seems promising as a predictive marker for maternal morbidity in hypertension in pregnancy. Its performance as a tool in the monitoring of progressing disease should be evaluated further in larger cohorts. Delivery before the eGFR_{cystatin C}/eGFR_creatinine-ratio decreases to, or below, 0.60 might help avoid maternal complications.

The erythrocyte sedimentation rate (ESR) is a widely used diagnostic test, influenced by all physiological and pathological conditions that can bias blood rheology by interfering factors. This study aimed to evaluate the performance of the CUBE 30 touch ESR analyzer in samples with preanalytical variables, as lipemia, hemolysis, and icterus or in presence of fibrinogen., Moreover we focused to define the maximum time limits to ensure a reliable ESR measure. Accuracy, intra-run and inter-run precision, and stability studies were performed. Moreover, hemolytic, jaundiced, lipemic samples and fibrinogen sensitivity were analyzed for interference study. Statistical analyses were performed. CUBE 30 touch and Westergren method comparison showed no statistical differences (Spearman Coefficient, R²=0,95). In the intra-run precision, the CV% mean obtained on samples with normal ESR level was 8,9%; with middle ESR level was 5,9% and with high ESR level the CV% was 4,3%. Inter-run precision test showed CV% of for single samples and overall samples in the range (12,3% for normal level and 4,8% for abnormal level). The samples stored at 4 °C showed good stability up to 3 h from collecting time. ESR samples showing lipemia, hemolysis or jaundice showed good correlations with the gold standard method (R² 0,901, 0,940, 0,911; p < 0,0001), however, Westergren tests were more sensitive than CUBE 30 touch to fibrinogen additions. The high comparability with the Westergren method, both in normal and interfering samples, and the good precision, support the usefulness of CUBE 30 touch in the clinical routine laboratory.

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.

To overcome the challenges of a manual leukocyte differential count, we have developed FlowDiff, an 8-colour, single tube flow cytometry panel, and investigated whether it could potentially replace the manual differential in our laboratory. The instrument was set up in accordance with the EuroFlow settings, and the protocol comprised a stain-lyse no wash process, taking approximately 30 min of working time, without the addition of a toxic lysis reagent. We found a very good correlation for all leukocyte populations between FlowDiff and the Sysmex XN analyzer in 80 normal, non-flagged samples. In addition, FlowDiff showed a very good correlation with manual differential in 168 abnormal samples, as well as a high diagnostic accuracy. FlowDiff correctly identified all samples with acute leukemia (N = 13) and differentiated all B-lymphomas (N = 49) in samples with lymphocytosis. Moreover, FlowDiff detected an additional five samples with B-lymphocytosis without any prior hematological malignancy, which turned out to be a B-lymphoma. Our data suggest that FlowDiff, our 8-colour flow cytometry-based differential, is comparable to, and can successfully substitute the manual differential.

Measuring plasma albumin is a common and important laboratory test. We compared the results obtained with the bromocresol green (BCG) colorimetric, immunoturbidimetric (IT), and capillary electrophoresis (CE) methods and evaluated the clinical reliability of the colorimetric test. Samples from 320 patients including 227 patients with hypoalbuminemia (albumin levels <35 g/L) were analyzed. Results were compared between different patient groups. The BCG method indicated significantly higher plasma albumin levels than the CE and IT methods, especially in patients with elevated C-reactive protein, alpha-1 globulin (a1G), and alpha-2 globulin (a2G) values. A significant proportion of patients with mild hypoalbuminemia tested using the BCG method (alb_BCG) and were classified as severely hypoalbuminemic (albumin <20 g/L) when switching to the CE or IT method (alb_CE and alb_IT). These patients had elevated a1G and/or a2G levels. This change of result implied an additional indication for albumin replacement therapy. The BCG method significantly overestimates albumin levels in patients with inflammation and hypoalbuminemia, which may lead to inappropriate therapeutic decisions.

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.

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.

We investigated serum concentrations of specific inflammatory parameters in patients with significant carotid artery stenosis (CAS) of 50-99%, with an additional focus on patients with moderate stenosis (50-69%), in terms of both symptomatic status and plaque morphology, to determine whether there are certain parameters that can be associated with plaque instability before the progression of CAS to a high degree. The study included 119 CAS patients, 29 of whom had moderate stenosis, and 46 controls. Ultrasonography of the carotid arteries was performed using color flow Doppler and B-mode duplex ultrasound, and serum inflammatory parameters were measured using commercially available enzyme immunoassays. When comparing patients with 50-99% stenosis, only serum amyloid A (SAA) was higher in symptomatic patients, while in the group of patients with 50-69% stenosis, myeloperoxidase (MPO) was higher and pentraxin-3 (PTX-3) was lower in symptomatic compared to asymptomatic patients, and soluble urokinase plasminogen activator receptor (suPAR) was higher in patients with carotid plaque of unstable compared to stable morphology. Our results suggest that the importance of different inflammatory parameters in patients with moderate CAS is not the same as in CAS patients in general, and therefore their separate investigation in patients with high and moderate stenosis may be beneficial. SAA has the potential to be further considered in research to predict CAS symptom risk. There is a possibility that MPO and PTX-3 play a role in the development of CAS symptoms originating from less stenotic plaques and that suPAR is involved in the destabilisation of such plaques.