Clinica Chimica Acta最新文献

Methemoglobinemia caused by hemoglobin M variants is a rare inherited hemoglobinopathy characterized by lifelong cyanosis and discordant oxygen measurements. We report an 18-year-old male presenting with marked cyanosis, chocolate-brown blood, markedly reduced arterial oxygen saturation, normal arterial partial pressure of oxygen, and elevated methemoglobin levels. Complete blood count analysis on a Sysmex XN hematology analyzer revealed a global downward shift of fluorescence signals on the leukocyte differential scattergram with apparent pseudoeosinophilia, whereas parallel analysis on an ADVIA 2120 analyzer showed a normal leukocyte differential. Peripheral blood smear examination demonstrated no morphologic abnormalities. Hemoglobin electrophoresis and whole-genome sequencing identified a heterozygous HBB:c.190C > T (p.His64Tyr) mutation, confirming the diagnosis of Hb M Saskatoon-associated methemoglobinemia. This case highlights methemoglobin as an important but underrecognized source of analytical interference in fluorescence-based leukocyte differential analysis and underscores the need for integrated interpretation of scattergram features, cross-platform verification, and clinical context in automated hematology testing.

Studies have reported that the prevalence of aggression is higher in individuals with schizophrenia compared to the general population. Various factors, including genetic variations, contribute to the emergence of aggression in patients with schizophrenia. Among these, the monoamine oxidase A (MAOA) and brain-derived neurotrophic factor (BDNF) genes are considered key genetic factors potentially influencing aggressive behavior in schizophrenia. This study investigated the association of BDNF rs6265 and MAOA rs1465108 polymorphisms with aggression in schizophrenia. A total of 150 patients diagnosed with schizophrenia were included in the study. The MAOA rs1465108 and BDNF rs6265 polymorphisms were analyzed using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method. Aggression was evaluated using the Buss-Perry Aggression Questionnaire. Suicide risk, childhood trauma, and impulsivity which were related to aggression were evaluated using the Suicide Probability Scale, the Childhood Trauma Questionnaire, and the Barratt Impulsiveness Scale, respectively. Negative and positive symptoms of schizophrenia were assessed using the Scale for the Assessment of Negative Symptoms (SANS) and the Scale for the Assessment of Positive Symptoms (SAPS), respectively. No direct genotype associations were observed between aggression and the BDNF rs6265 and MAOA rs1465108 polymorphisms. However, impulsivity, SAPS, and SANS scores were significantly associated with aggression. These findings highlight that aggression in schizophrenia is primarily shaped by environmental and clinical factors rather than by BDNF or MAOA variants.

Introduction: Autism Spectrum Disorder (ASD) is a neurodevelopmental condition marked by social communication deficits and repetitive behaviors. Evidence suggests that metabolic and mitochondrial stress contribute to ASD. Fibroblast growth factor 21 (FGF-21) and growth differentiation factor 15 (GDF-15) are circulating markers of mitochondrial dysfunction and cellular stress, but their role in pediatric ASD remains underexplored.

Methods: Case-control study involved 118 children: 88 with ASD (DSM-5 criteria) and 30 healthy controls matched by age and sex. ASD patients were divided by Autism Behavior Checklist (ABC) scores into Group I (ABC >60, n = 48) and Group II (ABC ≤60, n = 40). FGF-21 and GDF-15 were measured by ELISA. Biochemical parameters, hemogram, plasma amino acids (LC-MS/MS), and urinary organic acids (GC-MS) were analyzed. Statistical analyses included Kruskal-Wallis, Spearman correlation and ROC.

Results: FGF-21 was significantly elevated in ASD compared to controls (p < 0.0001), while GDF-15 showed no difference (p = 0.797). FGF-21 did not differ between Group I and Group II (p > 0.05). ASD showed increased lactate, lactate/pyruvate ratio, urea, AST, LDH, LDL, lymphocyte and platelet counts, and decreased pyruvate, serum and urinary creatinine (p < 0.05). Essential and branched-chain amino acids decreased, whereas glycine and histidine increased (p < 0.05). FGF-21 correlated weakly but significantly with mitochondrial dysfunction and amino acid metabolism markers. ROC showed good diagnostic accuracy for FGF-21 in ASD (AUC = 0.817), with 98.9% sensitivity and 73.3% specificity at 27.9 pg/mL cut-off. Urinary organic acids, methylmalonic acid, tiglylglycine, and 2-ketoisocaproic acid, were significantly elevated (p < 0.05).

Conclusion: Elevated serum FGF-21 in children with ASD is linked to metabolic alterations, whereas GDF-15 remains unchanged. These results suggest FGF-21's association with metabolic dysregulation in ASD.

Background: Intraoperative measurement of parathyroid hormone (PTH) levels in aspirate washings from excised tissue (aIOPTH) is an adjunctive technique used to confirm removal of parathyroid tissue. However, published protocols for aIOPTH testing vary, particularly in defining threshold values for confirming parathyroid tissue. This study assesses the diagnostic performance of both absolute aIOPTH values and aspirate-to-serum PTH ratios (aIOPTH:sIOPTH) in identifying parathyroid tissue, and reports biochemical cure rates in patients undergoing aIOPTH-guided parathyroidectomy.

Methods: We retrospectively analyzed aIOPTH testing in patients undergoing parathyroidectomy at a single tertiary-care center. Absolute aIOPTH concentrations and aIOPTH:sIOPTH ratios were compared to final histopathologic diagnoses to assess sensitivity and specificity. Biochemical cure was evaluated in patients with primary hyperparathyroidism based on total serum calcium and PTH measurements obtained six-months postoperatively.

Results: A total of 209 specimens from 103 patients (93% with PHPT, 34% with multiglandular disease [MGD]) were evaluated. Of these, 87% were histologically confirmed as parathyroid tissue, with aIOPTH values ranging from 50 to 5000 pg/mL. Absolute aIOPTH thresholds demonstrated sensitivities between 0.90 and 1.00 and specificities ranging from 0.00 to 1.00. Ratio-based thresholds maintained a sensitivity of 0.99 but showed lower specificity (0.08-0.42). Biochemical cure was achieved in 96.9% of single adenoma cases and 93.3% of MGD cases.

Conclusion: While aIOPTH:sIOPTH ratios have been reported to offer strong diagnostic performance, our findings indicate more variable specificity in clinical practice. In this cohort, we observed higher diagnostic accuracy with absolute aIOPTH values and propose aIOPTH >5000 pg/mL be considered confirmatory for parathyroid tissue, with values between 1000 and 5000 pg/mL regarded as indeterminate.

Background: Plasma transthyretin (TTR) is routinely quantified in clinical laboratories, yet the structural heterogeneity of circulating TTR and its potential impact on laboratory measurement remain poorly characterized. In transthyretin amyloid cardiomyopathy (ATTR-CM), information on native circulating TTR forms is limited.

Methods: An analytically optimized native polyacrylamide gel electrophoresis (PAGE) followed by Western blotting for the characterization of TTR and retinol-binding protein 4 (RBP4) in human plasma was developed. Samples from 71 ATTR-CM patients and 71 age- and sex-matched controls were analyzed. Electrophoretic bands were characterized by data-independent acquisition mass spectrometry, and total TTR was measured by routine nephelometric assay.

Results: Three fractions of circulating TTR species were identified in both groups: low-molecular-weight species (MW, 37-50 kDa), intermediate- (50-100 kDa) and high-MW aggregates (>150 kDa). Free native TTR tetramers were detectable only in a minority of samples, while monomeric TTR was not observed. Mass spectrometry confirmed the presence of TTR across all fractions and verified the co-migration of TTR and RBP4 in the 100 kDa band. Nephelometric quantification of TTR was unaffected by TTR aggregation induced in vitro by lowering pH, whereas native PAGE revealed an aggregation pattern under acidic conditions that differed from that observed in plasma.

Conclusions: Native PAGE combined with proteomic validation enables the analytical characterization of circulating TTR forms in clinical plasma samples. This approach reveals a previously underappreciated structural heterogeneity of plasma TTR, supports the reliability of routine nephelometric assays for total TTR quantification and provides a complementary tool for laboratory investigation of TTR biology in ATTR amyloidosis.

Background: Defining reference intervals (RIs) for coagulation tests is challenging due to pre-analytical variability and the logistical difficulty of recruiting healthy donors. This study aimed to define RIs for Prothrombin Time (PT) and Activated Partial Thromboplastin Time (APTT) using a "Big Data" indirect approach and to evaluate the impact of pre-analytical and biological variables within a harmonized hospital network.

Methods: A multicenter retrospective study was conducted across nine Italian hospitals using shared analytical platforms (ACL TOP 50). Data from over 300,000 patients were analyzed using the indirect refineR algorithm, with local estimates aggregated via random-effects meta-analysis. Results were validated against direct methods performed on healthy blood donors.

Results: Indirect estimates showed strong concordance with direct methods. The harmonized upper reference limit (URL) for APTT ratio was 1.19, unaffected by inpatient inclusion. For PT ratio, the pooled URL was 1.25, decreasing to 1.17 when excluding inpatients, closely matching direct estimates (1.15). While preanalytical variables (tube manufacturer, reagent type and sample transportation) showed negligible impact, biological variables were significant drivers of variation. PT URL displayed a marked J-shaped increase after age 50, up to 1.35 after age 80, with males consistently exhibiting higher values than females.

Conclusions: Harmonizing RIs across a hospital network is feasible, as technical differences do not justify local partitioning. However, the substantial influence of age and sex on PT suggests that introducing stratified RIs for the patients with age > 50 and sex partitioning may be necessary to improve diagnostic specificity.

Background: Analytical errors in plasma phosphate measurement can result in inappropriate treatment. Meropenem, not previously known to affect plasma phosphate assays, was suspected to be the interferent after a case of negative phosphate measurement with abnormal reaction curve for a meropenem-containing specimen on the Roche Cobas 8000 Analytic System. We studied the effect of meropenem on Roche's phosphate assay and the utility of reaction curve analysis in interference detection.

Methods: Meropenem-spiked plasma specimens with a range of estimated meropenem concentrations were prepared by mixing pooled human plasma from 46 patients and 20 mg/mL meropenem in normal saline in predetermined volume ratios. The relationship between meropenem concentration and percentage difference on apparent phosphate concentration on Roche was recorded as an interferogram. Reaction curves generated by the analyzer were also examined.

Results: Percentage difference on apparent phosphate concentration on Roche increases with meropenem concentration, with < -100% difference (i.e. negative measured phosphate) at estimated meropenem concentrations of ≥9.3 mg/mL. The negative interference was within acceptable limits defined by the Royal College of Pathologists of Australasia at an estimated meropenem concentration of 1.3 mg/mL (>50× therapeutic levels). Reaction curves of meropenem-containing samples were markedly different from the control.

Conclusion: Meropenem leads to negative, spectral, concentration-dependent, platform-specific interference on Roche phosphate assay. Reaction curve analysis improves interference detection in automated biochemistry analyzers and should be implemented in the form of laboratory protocols to prevent analytical errors and patient harm.