Laboratory medicine最新文献

Background: The mortality and morbidity rates in children with lower respiratory tract infection (LRTI) remain high.

Objective: To describe the number of bacteria that is associated with leukocytes in differential diagnosis of bacterial, mycoplasma, and viral LRTI in children.

Methods: Sputum smears were Gram stained for counting single-morphology bacteria associated with leukocytes. The differential diagnostic values of bacterial number were assessed in children with LRTI.

Results: The area under the receiver operating characteristic (ROC) curve was 0.95 for bacterial number in the differential diagnosis of bacterial infection from mycoplasma and viral infections. The area under the ROC curve was 0.62 for procalcitonin and 0.94 for bacterial number in the differential diagnosis of bacterial infection from mycoplasma infection.

Conclusion: The number of bacteria associated with leukocytes in sputum was valuable and rapid in differential diagnosis of bacterial infection in children with suspected bacterial, mycoplasma, and viral LRTI.

Objective: The aim of this study was to evaluate the efficacy of metagenomic next-generation sequencing (mNGS) for the identification of Gram-negative bacteria (GNB) infections and the prediction of antimicrobial resistance.

Methods: A retrospective analysis was conducted on 182 patients with diagnosis of GNB infections who underwent mNGS and conventional microbiological tests (CMTs).

Results: The detection rate of mNGS was 96.15%, higher than CMTs (45.05%) with a significant difference (χ 2 = 114.46, P < .01). The pathogen spectrum identified by mNGS was significantly wider than CMTs. Interestingly, the detection rate of mNGS was substantially higher than that of CMTs (70.33% vs 23.08%, P < .01) in patients with but not without antibiotic exposure. There was a significant positive correlation between mapped reads and pro-inflammatory cytokines (interleukin-6 and interleukin-8). However, mNGS failed to predict antimicrobial resistance in 5 of 12 patients compared to phenotype antimicrobial susceptibility testing results.

Conclusions: Metagenomic next-generation sequencing has a higher detection rate, a wider pathogen spectrum, and is less affected by prior antibiotic exposure than CMTs in identifying Gram-negative pathogens. The mapped reads may reflect a pro-inflammatory state in GNB-infected patients. Inferring actual resistance phenotypes from metagenomic data remains a great challenge.

Objective: We studied the clinical and molecular features of a family with hypertrophic cardiomyopathy (HCM).

Background: A very heterogeneous disease affecting the heart muscle, HCM is mostly caused by variants in the proteins of sarcomeres. The detection of HCM pathogenic variants can affect the handling of patients and their families.

Methods: Whole-exome sequencing (WES) was performed to assess the genetic cause(s) of HCM in a consanguineous Iranian family.

Results: Missense likely pathogenic variant c.1279C>T (p.Arg427Cys) within exon 7 of the LMNA gene (NM_170707) was found. The segregations were confirmed by polymerase chain reaction-based Sanger sequencing.

Conclusions: Variant c.1279C>T (p.Arg427Cys) in the LMNA gene seemed to have been the cause of HCM in the family. A few LMNA gene variants related to HCM phenotypes have been recognized so far. Identifying HCM genetic basis confers significant opportunities to understand how the disease can develop and, by extension, how this progression can be arrested. Our study supports WES effectiveness for first-tier variant screening of HCM in a clinical setting.

Serum κ and λ free light chains can be markedly elevated in monoclonal gammopathies; consequently, serum free light chain (sFLC) immunoassays are susceptible to inaccuracies caused by antigen excess. As a result, diagnostics manufacturers have attempted to automate antigen excess detection. A 75-year-old African-American woman had laboratory findings consistent with severe anemia, acute kidney injury, and moderate hypercalcemia. Serum and urine protein electrophoresis and sFLC testing were ordered. The sFLC results initially showed mildly elevated free λ light chains and normal free κ. The pathologist noted that sFLC results were discrepant with the bone marrow biopsy, electrophoresis, and immunofixation results. After manual dilution of the serum, repeat sFLC testing revealed significantly higher λ sFLC results. Antigen excess causing falsely low sFLC quantitation may not be detected by immunoassay instruments as intended. Correlation with clinical history, serum and urine protein electrophoresis results, and other laboratory findings is essential when interpreting sFLC results.

Objective: The aim of this study was to investigate fatty acids, lipid mediator levels, and the desaturase index rates on different acute coronary syndrome types and their possible relationship with routine lipid parameters.

Methods: The study included 81 patients with myocardial infarction (MI), 20 patients with unstable angina pectoris, and 31 healthy people. Fatty acids, CD59, lipoxin A4, 8-isoprostane, serum lipids, albumin, C-reactive protein (CRP), and high sensitive troponin levels were measured in all participants.

Results: When the fatty acid groups were evaluated as a ratio of albumin, MUFA/albumin and SFA/albumin ratios were significantly higher in the MI group compared to the control group. Although CD59 and lipoxin A4 levels were higher in the control group, there was no significant differences between the groups. When lipoxin A4/CRP and CD59/CRP ratios were evaluated, the results were significantly lower than those in the control group.

Conclusion: Lipid mediators may be useful in treating atherosclerosis by contributing to the resolution of inflammation.

Objective: To determine whether there is a correlation between vitamin D levels and palindromic rheumatism (PR) as an at-risk phenotype of rheumatoid arthritis (RA).

Methods: A total of 308 participants were enrolled in this cross-sectional study. We recorded their clinical characteristics and performed propensity-score matching (PSM). Serum 25(OH)D3 levels were determined via enzyme-linked immunosorbent assay.

Results: Our PSM resulted in 48 patients with PR and 96 matched control individuals. The multivariate regression analysis we performed after the PSM did not show a significant increase in PR risk in patients with vitamin D deficiency/insufficiency. There was no significant correlation between levels of 25(OH)D3 and frequency/duration of attacks, number of joints affected, and duration of symptoms before diagnosis (P ≥ .05). Mean (SD) serum levels of 25(OH)D3 in patients with and without progression to RA were 28.7 (15.9) ng/mL and 25.1 (11.4) ng/mL, respectively.

Conclusion: Based on the results, we found no clear association between vitamin D serum levels and the risk, severity, and rate of PR progressing into RA.

Objective: To establish a new method for quantitative detection of house dust mite (HDM)-sIgE based on light-initiated chemiluminescence assay (LiCA).

Methods: The assay was established after optimizing the reaction conditions, and the assay performance was evaluated according to the clinical guidelines. Further, the results of LiCA were compared with those from the ELISA and ImmunoCAP methods.

Results: Coefficients of variation for repeatability ranged from 4.22% to 7.69%, and intermediate precision from 8.38% to 10.34%. The limit of blank (LoB), limit of detection (LoD), and limit of quantitation (LoQ) were 0.066 kUA/L, 0.165 kUA/L, and 0.171 kUA/L, respectively. The coefficient of correlation (r) between the results of LiCA and ELISA was 0.9263, and the r between the results of LiCA and ImmunoCAP was 0.8870.

Conclusions: A HDM-sIgE quantitation assay based on LiCA was established, which could be used as a new reliable analytical tool for the determination of HDM-sIgE.

Triploidy is a genetic occurrence in which the chromosome count is 3n = 69 with a double (2n) chromosomal contribution to the conceptus from one parent. Such pregnancies are usually nonviable and are estimated to account for approximately 1% of recognized conceptions and 10% of recognized miscarriages. Majority opinion is that fetal losses due to triploidies are caused by the presence of 2 copies of paternal chromosomes. In this study, we present a digynic monoandric triploid miscarriage from a 32-year-old G7P1051 at approximately 13 weeks gestation, in which 2 copies of the maternal chromosomes are present in the fetus. This unusual phenomenon is supported by nonmolar placental histology, chromosomal microarray, and short tandem repeat assays, with the latter 2 being discussed in detail. Furthermore, this study includes discussion of recurrent miscarriage, recurrent triploidy, and long-term clinical follow-up of the patient.

Objective: The aim of this study was to assess the oxidative stress (OS) levels and dynamic thiol-disulfide balance in preterm newborns with bronchopulmonary dysplasia (BPD).

Methods: This prospective study included newborns separated into 2 groups, those with BPD (case) or without BPD (control). The 2 groups were compared by clinical and laboratory findings. The OS parameters total oxidant status (TOS), total antioxidant status (TAS), OS index (OSI), native thiol (NT), and total thiol were measured within the first day after birth. Oxygen requirements were measured using the fraction of inspired oxygen (FIO2) recorded in the first hour after birth/admission and the average FIO2 within 28 days of the birth.

Results: Infants diagnosed with BPD had a significantly lower gestational age and birth weight and a lower 5-min Apgar score (P < .05). Infants with BPD also had a higher rate of respiratory distress syndrome, rate of use of surfactant therapy, duration of ventilation therapy, and duration of hospital stay compared with control (P = .001, P = .001, P = .001, and P = .001, respectively). Plasma TAS and NT levels of newborns with BPD were significantly lower than newborns without BPD (P < .05). In the BPD group, plasma TOS and OSI levels were significantly higher than in the control group.

Conclusion: We found that OS was increased in newborns with BPD. The clinical significance of this study will provide the clinician with a different perspective on BPD by determining the dynamic thiol disulfide balance.

Objective: The acid/molybdate assay performed on the Beckman Coulter AU5821 could be subject to paraprotein interference, which potentially results in spurious hyperphosphatemia. We attempted to find a reliable solution to eliminate paraprotein interference in laboratory test results and discuss the causes of paraprotein interference.

Methods: We observed 50 multiple myeloma patients with serum paraproteins. We used the trichloroacetic acid (TCA) deproteinizing method to confirm that paraproteins indeed interfered with phosphate detection in the serum acid/molybdate assay. Furthermore, we used the dry chemical method (Vitros 5.1 FS, Johnson) and deionized water (H2O), normal saline (NS), and healthy human serum as alternative diluents. We assessed the clinical acceptability of the 4 methods by evaluating a bias percentage (bias%) lower than 10% under the premise of TCA treatment as a serum phosphate reference method.

Results: In total, comparing the results of the TCA treatment on the Beckman Coulter AU5821, 3/50 (6%) multiple myeloma patients exhibited phosphate pseudo-elevation (bias% >10%). Additionally, we found pseudo-hypophosphate only in immunoglobulin (Ig)G-kappa paraprotein samples, and all were above 50 g/L. The bias% between TCA and dry chemical method for the 3 patients was below 10%. The maximum acceptable dilutions for patient 22 were 8-fold H2O, 4-fold H2O , and 2-fold serum; those for patient 45 were 16-fold H2O, 16-fold H2O, and 2-fold serum. However, the bias% of patient 40 was beyond the acceptable range in all 3 dilution groups.

Conclusion: High concentrations of IgG kappa-type paraproteins are more likely to interfere with serum phosphorous detection. Both the TCA and dry chemical method can effectively eliminate paraprotein interference.