Scandinavian Journal of Clinical & Laboratory Investigation最新文献

Background: The direct antiglobulin test (DAT) is a key diagnostic tool in evaluating autoimmune haemolytic anaemia. However, indiscriminately ordering this test, together with certain methodological limitations, can compromise the efficiency of the clinical laboratory. This study aimed to develop and validate a predictive equation to identify negative results, optimising the use of DAT while maintaining the quality of care.

Methods: Through the laboratory information system (LIS), 1155 data were obtained from patients requesting DAT. A multiple logistic regression analysis was performed based on magnitudes related to haemolytic anaemia to obtain the best predictive model. The predictive equation obtained was: p = 1/(1 + e^-z) where 'P' represents the probability that the DAT is positive and 'z' the equation with the variables included in the model. Subsequently, its diagnostic efficiency was evaluated using a receiver operating characteristic curve. Finally, the equation was validated using a new cohort of data (N = 164).

Results: The 'z' value obtained from the best predictive equation was: $z=-2.884\hspace{0.17em}-\left(0.373\text{\hspace{0.17em}x\hspace{0.17em}Haptoglobin}\right)+\left(0.312\text{\hspace{0.17em}x\hspace{0.17em}\%Ret}\right).$ For the selected threshold, the equation demonstrated a sensitivity of 81.6%, a negative predictive value of 95.8%, and an area under the curve [95% confidence interval] of 0.812 [0.760-0.864]. According to the proposed equation, the performance of 61.6% of DAT would be reduced.

Conclusions: The proposed equation has an excellent predictive ability for negative DATs. Its simple integration into the LIS confirms its applicability in routine clinical laboratory practice, providing an effective screening tool for optimising DAT demand and managing resources efficiently.

Pneumatic tube systems (PTS) are routinely used in many hospitals for transporting collected body fluid samples and to reduce turnaround time. However, their use for transport of CSF is not widespread, in part due to ambiguous or non-existing data regarding possible impact on sample stability caused by PTS. This study investigates the effect of PTS transport on cell counts in CSF as well as on haemolysis. No statistical differences were observed on cell count for erythrocytes, leukocytes, lymphocytes, neutrophils, or monocytes as well as on haemolysis measured as absorbance at 415 nm. Therefore, it should be possible to use a PTS to transport CSF for these analyses.

Objective: To investigate chemiluminescence immunoassay (CLIA) in detecting anti-centromere antibodies (ACA) in primary biliary cholangitis (PBC) patients.

Methods: In this retrospective study, 165 patients diagnosed with PBC at Hangzhou Xixi Hospital between December 2020 and January 2023 were enrolled. ACA positivity was assessed using three methods: indirect immunofluorescence (IIF), line immunoassay (LIA), and CLIA. The agreement among the methods was evaluated using kappa statistics and correlation analysis. Logistic regression was used to assess the association between ACA positivity and portal hypertension. Receiver operating characteristic (ROC) curve analysis was performed to compare the predictive performance of CLIA and LIA for portal hypertension.

Results: Among the 165 PBC patients, 69 (41.8%), 68 (41.2%), and 66 (40.0%) were ACA-positive by IIF, LIA, and CLIA, respectively. CLIA showed excellent agreement with IIF (κ = 0.962) and LIA (κ = 0.975), and a strong correlation with LIA in quantitative detection (R = 0.893, p < 0.001). Logistic regression confirmed that ACA positivity was significantly associated with portal hypertension (OR = 2.726, 95% CI: 1.437-5.169, p = 0.002). CLIA demonstrated superior predictive performance over LIA for portal hypertension (AUC: 0.705 vs. 0.638, p = 0.001).

Conclusion: CLIA exhibits excellent concordance with conventional methods for detecting ACA and provides a broader linear range for quantitative assessment. ACA positivity was significantly associated with portal hypertension in PBC patients. The main advantage of CLIA lies in its precise quantification of ACA and prognostic value, highlighting its potential role in risk stratification and disease monitoring in PBC patients.

Blood gas analyzers (BGAs) offer rapid results and operational convenience in emergency settings, whereas laboratory auto analyzers (LAAs) remain the reference standard despite slower processing. This study compared BGA and LAA measurements of sodium (Na), potassium (K), hemoglobin (Hb), and hematocrit (Hct). A secondary aim was to evaluate their agreement across acid-base subgroups and in cases of severe acidosis. This study included ≥18 years patients from January 1 to June 30, 2024. BGA and LAA results were compared overall and across acid-base subgroups. Patients with pH <7.20 were analyzed separately as the severe acidosis group. Bland-Altman analysis showed the following mean differences and 95% limits of agreement: Na, 1.36 ± 2.33 mmol/L (-3.21 to 5.92); K, 0.221 ± 0.197 mmol/L (-0.166 to 0.607); Hb, 0.531 ± 0.649 g/dL (-0.742 to 1.804); and Hct, 1.68% ± 2.60 (-3.42 to 6.78). At clinical decision thresholds, BGA demonstrated varying diagnostic performance with sensitivities and specificities of 56.9% and 95.8% for hyponatremia, 67.5% and 98.7% for hypernatremia, 95.4% and 95.6% for hypokalemia, 48.7% and 99.8% for hyperkalemia, and 73.4% and 99.9% for transfusion decisions, respectively. In patients with severe acidosis, correlations remained strong, though agreement limits were notably wider. BGA-derived K values showed acceptable agreement with LAA and may be used interchangeably. Hb and Hct did not meet agreement criteria, while Na may be acceptable with clinical correlation. In severe acidosis, none of the parameters achieved acceptable agreement, indicating that BGA results should be interpreted with caution in this subgroup.

Low-density lipoprotein cholesterol (LDL-C) remains a key biomarker for cardiovascular risk assessment. While the Friedewald equation is widely used for estimating LDL-C, its accuracy can vary across populations and analytical platforms. This study aimed to develop and validate population-specific, platform-adapted LDL-C equations in two independent cohorts and to compare their performance with the Friedewald equation. A retrospective analysis was conducted using lipid profiles from 31,265 individuals across two datasets: a tertiary hospital (n = 10,174; Roche Cobas platform) and a private laboratory (n = 21,091; Abbott Alinity platform). For each, two linear regression models (50:50 and 80:20 random training-validation splits) were used to develop LDL-C estimation equations using total cholesterol, high-density lipoprotein cholesterol, and triglycerides as predictors. Performance was evaluated by median absolute error (MAE), median percentage error (MPE), and agreement with direct LDL-C in clinical risk categories. The training/validation models performed nearly identically; therefore, only the 50:50 models were retained for the final analysis, with one equation generated for each platform. Both novel equations showed significantly lower MAE (-0.015 to -0.010 mmol/L) and MPE (-0.5% to -0.4%) compared to the Friedewald equation (-0.217 and -0.209 mmol/L MAE; -7.4% and -6.6% MPE) and had more balanced error distributions. The Roche Cobas-derived equation achieved higher overall classification accuracy (85.1%) than the Abbott Alinity-based model (78.6%), while both substantially outperformed Friedewald (67.1% and 65.3%) in all but the <1.03 mmol/L LDL-C category. Platform-specific, population-adapted LDL-C equations offer superior accuracy and risk classification over Friedewald. These findings further support the clinical relevance of implementing such equations; however, broader validation and formal guidance from professional bodies are needed to facilitate their integration into clinical practice.

Hematology laboratories routinely face analytical challenges despite automation and standardized workflows. While Six Sigma metrics are increasingly applied in clinical chemistry, their use in hematology remains limited due to variability in Total Allowable Error (TEa) standards and lack of integrated assessment tools. This study aims to evaluate analytical performance in hematology by combining sigma metrics with an innovative graphic decision tool to guide quality control (QC) planning. A retrospective study over was conducted in a tertiary hematology lab. Internal Quality Control (IQC) and External Quality Assurance Scheme (EQAS) data for five analytes-hemoglobin, WBC, RBC, hematocrit, and platelet count-were analyzed using the Six Sigma model. TEa values were selected using a hierarchical approach based on the 2014 Milan Consensus, prioritizing biological variation, CLIA, and RCPA guidelines. A novel graphic tool was used to visualize performance zones and inform QC strategies. Sigma metrics varied across parameters and TEa sources. Hemoglobin demonstrated excellent performance (σ > 6), while hematocrit and platelet count showed sigma <3 under strict TEa. Graphic tool stratification revealed actionable insights; application of TEa optimization reclassified low-performing tests, significantly improving QC efficiency. Subsequent QGI calculations identified the predominant source of error. This study introduces a first-time application of a graphic tool in hematology for sigma visualization and QC planning. The dual-framework approach enhances diagnostic accuracy and resource utilization, offering a practical, scalable model for laboratories seeking personalized, risk-based quality management.

There is limited evidence regarding the role of circulating neutrophil gelatinase-associated lipocalin (NGAL) in patients admitted with complications of cirrhosis. This prospective cohort study evaluated 161 adult patients hospitalized for acute decompensation (AD) of cirrhosis, with serum samples collected within 48 h of admission. The aim was to investigate the association between NGAL levels, acute kidney injury (AKI), and patient outcomes. Sixty patients presented with AKI at admission. Serum NGAL was independently associated with AKI (OR 1.019, 95% CI 1.012-1.027; p < 0.001), with levels increasing across AKI stages: no AKI (94.24 µg/L), stage 1 (179.20 µg/L), stage 2 (235.50 µg/L), and stage 3 (257.85 µg/L; p < 0.001). Hepatorenal syndrome (HRS) was associated with significantly higher NGAL compared to pre-renal AKI (259.70 vs. 179.30 µg/L; p = 0.002). NGAL predicted HRS with an AUROC of 0.837 (±0.064), with a negative predictive value of 94% for NGAL < 215.00 µg/L. It also predicted AKI reversibility, with an AUROC of 0.829 (±0.061) and a positive predictive value of 98% for NGAL < 242.00 µg/L. Furthermore, NGAL independently predicted 30-day mortality, with a survival probability of 90.8% for NGAL < 160 µg/L and 66.7% for NGAL ≥ 160 µg/L (p < 0.001). These findings support the clinical utility of circulating NGAL as a biomarker reflecting AKI phenotype and disease severity in patients acutely hospitalized for cirrhosis-related complications, with prognostic relevance.

Familial hypocalciuric hypercalcemia (FHH) is a genetically heterogeneous autosomal dominant disorder of calcium homeostasis, which is usually asymptomatic and characterized by low or normal phosphorus, inappropriately normal or elevated PTH, and low fractional excretion of calcium (FECa) in addition to hypercalcemia. Loss-of-function mutations in the G protein subunit alpha 11 (GNA11) gene, an important downstream signaling partner of the Calcium-sensing receptor (CaSR), cause FHH type 2. We reviewed the GNA11 gene-associated FHH type 2. A 14-year-old male was referred due to hypercalcemia (2.89 mmol/L). Slightly elevated PTH (7.95 pmol/L), but normal phosphorus (1.19 mmol/L), alkaline phosphatase (271 U/L), magnesium (0.95 mmol/L), and albumin (43 g/L) levels were detected. The FECa was found to be low when serum calcium was high (FECa was <0.01%, and <0.01% on two separate tests). A homozygous c.301T > C, p.Y101H variant was detected in the GNA11 gene. The same variant was detected heterozygous for both parents. While the calcium levels of the mother and father were normal, their spot urinary FECa was found low (Ca: 2.47 mmol/L, FECa: <0.01%, and Ca: 2.45 mmol/L, FECa: 0.01%, respectively). Hypocalciuria without hypercalcemia can be detected in cases heterozygous for the GNA11 gene mutation. Severe hypercalcemia may not occur in homozygous cases.

Early kidney function decline may be associated with reduced filtration of middle-sized molecules, currently defined as selective glomerular hypofiltration syndrome (SGHS), and driven by the accumulation of atherosclerosis-promoting proteins. We aimed to investigate whether SGHS and other markers of kidney function are associated with subclinical atherosclerosis as evaluated by intima-media thickness (IMT) in the carotid arteries, and whether these associations differ by sex. Data from 2,902 individuals in the 'Malmö Diet Cancer Study', with a mean age of 56 years ± 6, none of whom had a prior diagnosis of cardiovascular disease or diabetes, were followed for 17 years (IQR 2). Kidney function was estimated using glomerular filtration equations based on cystatin C and creatinine (eGFRcys and eGFRcr). The ratio eGFRcys/eGFRcr was used to assess glomerular filtration capacity and eGFR slopes were calculated. Two indices of atherosclerosis were utilized: (1) IMT of a. carotis communis (IMT_CCA), (2) IMT of the far wall of the carotid bulb, both at baseline and follow-up (IMT_BULB). In women, the eGFRcys/eGFRcr ratio was associated with the annual progression of IMT_BULB. Additionally, the eGFRcys/eGFRcys ratio was associated with IMT_BULB values greater than 1.5 mm at follow-up. In men, only eGFRcys slope was predictive of being in the sex-specific 75^th percentile of IMT_CCA at follow-up; no such association was found in women. Overall, SGHS was associated with the progression of IMT_BULB, plaque presence, and greater IMT thickness at follow-up in women. In men, only a faster decline in eGFRcys was associated with plaque presence (IMT_BULB above 1.5 mm), independent of traditional cardiovascular risk factors.

The concentration of methylmalonic acid (MMA) in plasma increases in patients with cobalamin deficiency (CD). Independent of the cobalamin status, MMA also increases with decreasing glomerular filtration rate (GFR). Therefore, the physician who assesses MMA values must consider the patients' renal function. In order to avoid intuitive assessments, we have suggested that the laboratory should adjust MMA to an estimated GFR (eGFR) value of 100 mL/min/1.73 m². We named this measure MMA₁₀₀ (Åsberg et al.). Now, we used a large clinical data set to compare three characteristics of MMA₁₀₀ and MMA: The relation to eGFR, the diagnostic accuracy, and the upper reference limits for various age groups. In this material, MMA₁₀₀ was not totally unrelated to eGFR, but far less so than MMA. MMA₁₀₀ also had a higher diagnostic accuracy than MMA. The upper reference limits of MMA₁₀₀ varied less with age than those of MMA. In conclusion, MMA₁₀₀ was a better biomarker of CD than MMA.