Scandinavian Journal of Clinical & Laboratory Investigation最新文献

Data on the long-term within-subject biological variation (CV_I) of serum thyroid stimulating hormone (S-TSH) are scarce. In the EFLM Biological Variation Database, the longest observation period was one year. We estimated a coefficient of variation that included analytical variation (CV_I+A) using data from 16,976 individuals in the Trøndelag Health Study (HUNT), where S-TSH was measured on two occasions with an average interval of 10.6 (range 9.3-12.3) years. These individuals reported their health to be 'good' or 'very good' on both occasions and were not registered with any diagnoses or use of medications (according to Norwegian Prescribed Drug Registry) related to the thyroid. We used the software refineR to identify an assumed nonpathological subpopulation in the distribution of distances from each observation to the center of the bivariate distribution of the two S-TSH-values. From this subpopulation, individuals with a distance ≤ the 95 percentile in the distribution of distances were selected for estimation of CV_I+A. The difference in percent of the mean (DPM) was calculated for each individual, and CV_I+A as the standard deviation in the distribution of DPMs divided by 2^0.5. This method was robust against systematic bias between the two measurements. CV_I+A was 21-23% for different groups of age and sex. Accounting for CV_A would imply a CV_I 0.1-0.8% less than CV_I+A. Our estimates are well within the 12-29.3% range of CV_I reported from the seven studies in the meta-analysis of the EFLM Biological Variation Database.

Soluble urokinase plasminogen activator receptor (suPAR) is an inflammatory marker that has been shown to predict poorer outcomes in cardiovascular disease and after cardiac surgery. The relationship between suPAR concentrations and postoperative complications after valvular surgery, however, remains unclear. This study aims to evaluate the predictive value of suPAR concentrations for infection, acute kidney injury (AKI) and prolonged mechanical ventilation after valvular surgery. This prospective, observational, single-centre study included 414 patients who underwent valvular cardiac surgery at Skåne University Hospital between 1 February 2020 and 22 September 2021. Early postoperative suPAR levels were measured, and multivariable logistic regression was used to identify significant risk factors for postoperative infection, AKI and prolonged mechanical ventilation. Left ventricular ejection fraction (LVEF) 30-50% (OR 3.57 [1.29-9.86], p = 0.014) and suPAR concentration (OR 1.41 [1.56-1.71], p <0.001) were found to be predictive risk factors for developing postoperative infection. Additionally, suPAR concentration (OR 1.23 [1.05-1.43], p = 0.008), cardiopulmonary bypass (CPB) time (OR 1.01 [1.00-1.02], p = 0.004) and age (OR 1.04 [1.01-1.08], p = 0.007) were found to be predictive risk factors for postoperative AKI. However, suPAR concentration did not predict prolonged mechanical ventilation. Plasma suPAR levels after cardiac valve surgery were found to be predictive of postoperative AKI and infection. Our results indicate that early postoperative suPAR measurements may be a valuable tool for identifying patients at higher risk for developing postoperative complications.

Introduction: Monitoring CD3+, CD4+ and CD8+ T lymphocytes count is used in patients with known HIV infection, to determine efficacy of antiretroviral medication. Sometimes, due to the long distance, more time is needed for the sample to reach a more equipped laboratory. The aim of our study was to evaluate the impact of prolonged pre-analytical storage of blood at temperature, 96 h at room temperature, on the quality of results for the three parameters.

Methods: The analysis of 60 EDTA-anticoagulated blood samples, stored at room temperature (15-25 °C) after sampling, was conducted after 24 h and 96 h, respectively. The BD FACSLyric^™ system was used to identify and enumerate CD3+, CD4+, and CD8+ T lymphocytes.

Results: Following a 96-hour period, no notable discrepancies were observed in the data for CD3+, CD4+, and CD8+ T lymphocytes. Passing-Bablok regression analysis showed no significant difference in y-intercept and slope. The Pearson correlation coefficient (r) demonstrated a significant and strong correlation with rho values of 0.994, 0.992, and 0.996, respectively. The analytical agreements demonstrated that all results fell within the total allowable margin of total error.

Conclusion: The results of this study demonstrated that diagnostic samples, monitored for CD3+, CD4+ and CD8+ T lymphocytes, could be stored for up to 96 h without compromising the quality of the results.

The concentration of chromogranin A in serum (s-CgA) is a general marker of neuroendocrine neoplasms. Unfortunately, s-CgA is increased in several other clinical conditions, including renal failure. The physician who assesses s-CgA values must consider the patients' renal function. How this should be done is not clear. We developed an adjustment formula from the association between median s-CgA and the estimated glomerular filtration rate (eGFR) in 2708 patients where s-CgA was measured by the CgA II KRYPTOR method. We used multivariable fractional polynomial quantile regression with the model ln(s-CgA) = c₀ + c₁ × sex + c₂ × age + c₃ × eGFR, thus accounting for sex and age. The final adjustment formula could be simplified to s-CgA₁₀₀ = (eGFR / 100) × s-CgA, where s-CgA₁₀₀ is an indication of what s-CgA would be if eGFR in the same patient was 100 mL/minute/1.73 m². In patients with eGFR > 100 mL/minute/1.73 m² no adjustment was done. We tested the formula on another patient population (n = 1563), where s-CgA was measured by a RIA method. S-CgA₁₀₀ proved to be independent of eGFR in that population. The clinical validity of s-CgA₁₀₀ must await further investigations.

Vitamin B12 (s-cobalamin) and methylmalonic acid (s-MMA) are often interpreted together to diagnose cobalamin deficiency, in context with patient symptomatology, which is many cases is unspecific. Today, clinicians assess test results in relation to the univariate reference limits or decision limits. As s-MMA depends on renal function (glomerular filtration rate, GFR), interpretation can be complicated. To ease the interpretation of the two measurements, we propose three new tools: First, we developed a new formula for adjusting s-MMA to an eGFR of 100 mL/min/1.73 m² (s-MMA₁₀₀). The formula was s-MMA₁₀₀ = [(eGFR/100)^0.549] × s-MMA. It was derived from the median relationship between s-MMA and estimated GFR (eGFR) in an ambulant patient population of 4342 individuals, where eGFR was calculated according to the EKFC equations. S-MMA₁₀₀ was not associated with eGFR in a US test population of 6852 individuals. Second, we constructed a combined reference range for s-MMA₁₀₀ and s-cobalamin from data in a healthy reference population (n = 495 individuals). Third, we proposed a new cobalamin deficiency index, CDI = s-cobalamin/s-MMA₁₀₀, and studied the effect of different decision limits on the prevalence of positive test results in a patient population. Using the 2.5 percentile of CDI in the reference population as a decision limit gave a prevalence of 5.2% positive test results in the patient population. However, as a gold standard for cobalamin deficiency does not exist, we were unable to study the diagnostic accuracy of the CDI. Therefore, the true diagnostic accuracy of these tools is yet unknown and should be investigated.

Backgrounds: Serum thyroglobulin immunometric assays (sTg) are crucial for monitoring differentiated thyroid cancer (DTC) treatment. However, challenges such as anti-thyroglobulin autoantibodies (TgAb) and assay variability hinder evaluations. This study assessed four sTg methods-three second-generation (Architect, Access, Elecsys) and one first-generation (Immulite)-following Clinical and Laboratory Standards Institute (CLSI) and American Thyroid Association (ATA) guidelines.

Methods: The study compared sTg_(Architect), sTg_(Access), sTg_(Elecsys), and sTg_(Immulite). Precision was evaluated per CLSI EP05-A3, while the lower limits of detection (LLD) were assessed using EP17-A2. Passing-Bablok and Bland-Altman analyses were conducted as per EP09c, and semi-quantitative comparisons used Kappa statistics.

Results: The second-generation sTgs (Architect, Access, Elecsys) exhibited satisfactory precision (<7% coefficient of variation, CV%), unlike sTg_(Immulite), which showed significant deviations and inadequate sensitivity for DTC recurrence (Limit of quantitation, LoQ = 4.59 μg/L). Second-generation sTgs had strong correlations (r > 0.884) across all concentration ranges (≤1, 1-10, >10 μg/L), with biases (slope: 1.131-2.027). sTg_(Immulite) correlated well with second-generation methods for concentrations >10 μg/L (r > 0.945) but less so for <10 μg/L (r < 0.642). TgAb significantly impacted sTg_(Immulite). Kappa statistics revealed strong agreement among second-generation methods (κ > 0.800) but lower concordance with sTg_(Immulite), especially in TgAb(+) samples (κ: 0.562-0.653). Agreement ratios were high for second-generation methods (0.667-1.000) but variable for sTg_(Immulite), particularly at lower concentrations and in TgAb(+) cases (0.097-0.727).

Conclusions: sTg_(Immulite) did not meet LLD and precision criteria for DTC monitoring, facing issues with TgAb interference. Second-generation sTgs demonstrated consistent performance across all concentrations.

Creatinine is a widely used clinical biomarker in adult and pediatric patients to estimate kidney function and glomerular filtration rate. There are however few recent studies that have addressed method performance in the creatinine range relevant for children. This study aimed to describe measurement performance in the pediatric concentration range by comparing commonly used enzymatic methods on four platforms: Abbott Alinity, Radiometer ABL800, Roche Cobas and Siemens Atellica, to the reference method isotope dilution mass spectrometry (IDMS). A secondary aim was to compare the Roche enzymatic methods by using dilutions of control sera issued by the Nordic Association of Clinical Chemistry. We found varying accuracy of the creatinine methods in the low concentration range. The relative difference between platforms, in an investigated range below 75 µmol/L, decreased as creatinine concentration increased. Using an absolute factor to correct for method bias as recommended by one of the manufacturers could hamper measurement trueness in the low concentration range. The in vitro diagnostic industry and stakeholders should strive towards creatinine measurement agreeability. Attention to the pediatric concentration range is needed when correcting for method bias.

Crystals in urinary sediment are commonly recognized structures, typically identified by a combination of crystal morphology and urine pH. In this paper, we present the first reported case of EDDP (2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidene) crystals, the primary metabolite of methadone, in a 67-year-old male with hepatorenal syndrome. Routine urinalysis revealed numerous needle-shaped crystals, which prompted further investigation. Advanced techniques, including Raman spectroscopy and mass spectrometry, confirmed the crystals to be EDDP. This case highlights the diagnostic challenge posed by drug-induced crystalluria, particularly in the context of complex comorbidities and chronic opioid therapy. Early recognition and identification of such crystals are crucial to preventing further kidney injury, emphasizing the importance of meticulous urine sediment analysis in clinical practice. This report broadens the spectrum of drugs known to induce crystal formation.

This study assessed the reliability of Roche Accu-Chek Inform II glucometers in a real-world setting. A retrospective analysis was conducted on 6,695 paired results. Capillary samples were tested using Roche Accu-Chek Inform II glucometers, while venous samples were analyzed using Roche Cobas c503/702 analyzers. Compliance was assessed using modified criteria based on the ISO 15197 guideline and the CLSI EP09-A3 guideline using Passing-Bablok regression analysis, Bland-Altman plots, and Surveillance Error Grid (SEG) analysis. The overall compliance of glucometer results within ±15% or 0.83 mmol/L (15 mg/dL) of the reference method was 81.5%, below the acceptance criterion of 94.6%. SEG analysis showed that 90.3% of the paired results fell within the No-risk zone, with less than 0.001% in the moderate/lower-risk zone. The Emergency Department results indicated 87.8% overall compliance and 92.2% of pairs falling in the No-risk zone. Based on the regression analysis, the glucometer results showed a positive constant bias of nearly 0.33 mmol/L (6 mg/dL). The Bland-Altman plots showed a positive mean difference of 0.43 mmol/L for results ≤5.55 mmol/L (≤100 mg/dL) and a positive mean percentage difference of 3.77% for results >5.55 mmol/L (>100 mg/dL), within the permissible deviation. The compliance values ranged from 76.0% to 90.3% for clinical concentration groups, with the highest compliance found between >16.65-22.20 mmol/L (>300-400 mg/dL). The Accu-Chek Inform II glucometers demonstrated in real-world reliability, with most results falling within acceptable risk categories. However, compliance still needs improvement, so manufacturers should assess opportunities for advancement.