Practical Laboratory Medicine最新文献

Objective

Abnormal serum matrix metalloproteinase-9 (MMP-9) levels are closely related to the occurrence and development of many diseases. This study aimed to establish a fluorescence immunochromatography (FIC) method using the lanthanide fluorescent element europium(III) (Eu³⁺) for the quantitative measurement of MMP-9 in serum.

Design & Methods

The FIC method for quantifying MMP-9 was optimized and established, and the FIC test strips (FICTS) were assembled and subsequently evaluated for sensitivity, specificity and precision. Furthermore, the reference interval and clinical sensitivity/specificity were estimated using clinical healthy/positive serum samples, and a commercial ELISA was used for comparison.

Results

We successfully established an FIC method and prepared FICTS. The analytical sensitivity of the FICTS was 0.92 ng/mL, with a linearity range of 0–1000 ng/mL. The cross-reactivity of the 7 common serum interferents was less than 1.56%. All recoveries of the intra-array and inter-array samples ranged from 102.50% to 110.99%, and all CVs were less than 5%. The reference interval of the FICTS was >161.15 ng/mL. The clinical sensitivity was 96.00%, and the specificity was 97.5%. The results of 270 clinical serum samples were highly coincident with the clinical diagnostic results. Pearson correlation analysis and Bland‒Altman plots indicated that the FICTS and commercial ELISA results were consistent with the quantitative MMP-9 concentration.

Conclusions

The designed FIC method and test strips may be suitable for point-of-care quantitative measurement of MMP-9, which provides a new method for screening for atherosclerosis, xerophthalmia, etc.

Introduction

Group B streptococcus(GBS)often causes adverse outcomes such as urinary system infection, intrauterine infection, premature birth, and stillbirth in perinatal women. Perinatal screening of GBS is conducive to guiding clinical scientific intervention and improving delivery outcomes.This study quantitative real-time PCR (RT-qPCR) combined with magnetic separation was used for GBS detection.

Materials and methods

Sample pre-treatment in this study involved the utilization of magnetic separation (MS) technology, aiming to expedite the detection process and enhance detection sensitivity, and the cfb gene of group B streptococcus was used as the target gene to establish quantitative real-time PCR (RT-qPCR) to detect group B streptococcus.

Results

It was found that penicillin-functionalized magnetic beads had a good ability to enrich and capture group B Streptococcus.The findings revealed an exceptional detection sensitivity, with the ability to detect B streptococcus in urine samples at levels as low as 10² CFU/mL.

Conclusions

The utilization of MS technology in conjunction with the RT-qPCR (MS-RT-qPCR) assay, as demonstrated in this study, offers a viable approach for prenatal screening of group B streptococcus among perinatal women.

Background

Since 2020, the National Health Security Office includes the human papillomavirus DNA testing for cervical cancer screening in the government's healthcare schemes. HPV DNA testing has become primary screening in many laboratories in Thailand. External quality assurance scheme is crucial for assessment of laboratory performance.

Objectives

The aim of this study was to develop a pilot program using LBC samples for the EQA of molecular methods and to review the methods used by participants to detect the presence of high risk HPV genotypes.

Study design

Four pilot distributions were shipped between December 2021 and May 2023, six months apart of two panels, each consisting of five different specimens.

Results

All participants achieved 100 % accuracy in correctly identifying the presence or absence of high-risk genotypes in all 5 EQA samples. The most used HPV DNA test for detecting the presence of high-risk HPV DNA was the two specific high-risk genotypes and 12 other high-risk HPV genotypes. There was an observed increase in the use of assays that could detect 14 HPV HR genotypes. It suggests expanding testing methods to include a broader range of high-risk HPV genotypes, which could improve the comprehensiveness of the testing.

Conclusions

The HPV DNA testing scheme provides a standardised, homogeneous and characterised clinical specimen. These results indicate that the LBC samples are suitable for utilisation in an EQA scheme. EQA of HPV molecular screening programme is essential for monitoring the performance of laboratory networks.

Objective

The 24-h urine protein remains the gold standard to diagnose proteinuria in suspected preeclamptic patients. However, this test is time consuming and sometimes inaccurate. In this study, we aimed to analyse the correlation between the random urine protein/creatinine ratio (UPCR) and 24-h urine protein and to explore the clinical value of UPCR in the diagnosis of preeclampsia.

Method

We retrospectively evaluated 109 pregnant women from our hospital who had hypertensive diseases. They were grouped according to time of urine collection and disease severity to compare differences in random urine protein, urine creatinine, and UPCR. The correlation between the UPCR and 24-h urine protein was determined by Pearson's linear correlation.

Results

We found no statistically significant differences in random urine protein, urine creatinine, or UPCR among the four time of sampling groups. Further, random urine protein, UPCR, and 24-h urine protein between the gestational hypertension and preeclampsia groups differed significantly (P < 0.001). Correlation analysis showed significant positive correlation between random urine protein, and 24-h urine protein, and UPCR and 24-h urine protein, with r values of 0.789 and 0.810, respectively. According to the receiver operating characteristic (ROC) curve, the optimal threshold, sensitivity, specificity, and area under the curve of UPCR for the diagnosis of preeclampsia were 0.456 g/mmol, 67.8 %, 78.3 %, and 0.747, respectively (95 % confidence interval [CI], 0.65–0.844).

Conclusion

This study indicated that UPCR is significantly correlated with 24-h urine protein and is expected to replace the 24-h urine protein test as a diagnostic indicator of preeclampsia.

Background

Vitamin D (vit-D) deficiency is highly prevalent in the Korean population, highlighting the need for accurate measurements. In this study, the interferences by endogenous and cross-reactive substances were compared between routine vit-D immunoassays and mass spectrometry (MS) methods.

Methods

Two MS methods and 4 immunoassays from different manufacturers (Abbott, Beckman Coulter, Roche, Siemens) were compared. Residual samples that were icteric, lipemic, hemolyzed, high in rheumatoid factor, from myeloma patients, or patients undergoing hemodialysis were collected. Also, 4 levels of National Institute of Standards and Technology (NIST) Standard Reference Material 972a, and 12 samples serially spiked with 3-epi-25-OH-D₃ were prepared.

Results

Significant interferences were observed in hemolytic (Roche), icteric (Beckman and Siemens) and lipemic samples (all 4 immunoassays). Level 4 NIST material and 3-epi-25-OH-D₃-spiked samples induced significant cross-reactivity, yielding higher total vit-D measurements in non-epimer-separating MS methods, and both the Beckman and Roche immunoassays.

Conclusion

Most observed interferences were consistent with manufacturers’ claims, but overall improvement of immunoassay bias limits is required. Awareness of potential interference is important to increase the accuracy of vit-D measurements. Moreover, care is due when interpreting vit-D results of newborns, infants and less commonly, pregnant women, who are known to have physiologically high levels of the highly cross-reactive 3-epi-25-OH-D₃.

C-reactive protein (CRP) is an established acute-phase marker for infection, inflammation and tissue injury, used to guide clinical decision-making in primary and secondary care. This study compared the analytical performance of the quantitative microfluidic point-of-care LumiraDx CRP Test to a laboratory-based reference method (Siemens RCRP Flex assay on the Dimension® Xpand®) and evaluated equivalence of sample matrices (blood versus plasma) in point-of-care settings using samples from patients presenting with symptoms of infection or inflammation. The LumiraDx CRP Test demonstrated close agreement with the lab reference test (range, 5.1 to 245.2 mg/L, r = 0.992, slope = 0.998, intercept = –0.476; n = 205) and notable agreement between fingerstick and venous blood and plasma (r = 0.974–0.983; n = 44). Paired replicate precision had mean coefficients of variation of 6.4 % (plasma), 6.6 % (capillary direct) and 8.1 % (venous blood); overall error rates were 2.9 %. The quantitative LumiraDx CRP Test showed robust analytical performance across sample matrices and close agreement compared to the laboratory reference method when used at the point of care.

Objectives

High-performance liquid chromatography (HPLC) is commonly used to measure hemoglobin A_1c (HbA_1c) levels and detect hemoglobin variants (Hb-Vars). HLC-723GR01 (GR01) is a new-generation automated ion-exchange HPLC system with two switchable analysis modes, namely short (30 s/test) and long modes (50 s/test). We evaluated the general performance of both analysis modes of GR01 for quantifying HbA_1c and detecting Hb-Vars.

Design and methods

We evaluated the instrument's precision based on CLSI protocol EP-05-A3. A comparison of the two analysis modes of GR01 against the standard mode of HLC-723G11 was performed on 100 whole blood samples. The GR01 long mode was compared with affinity HPLC (AF-HPLC) for detecting common Hb-Vars (HbE, HbD, HbS, and HbC, >20 samples). To examine the detection capability for minor Hb-Vars, we analyzed 26 Hb-Vars using multiple analyzers, including both analysis modes of GR01.

Results

Both modes of GR01 had within-laboratory coefficients of variation of ≤1.0 % from four samples with HbA_1c concentrations of 32–86 mmol/mol. Good correlation was observed between GR01 and HLC-723G11. The results for HbA_1c detection in the presence of the major variants revealed a strong correlation between the long mode of GR01 and AF-HPLC (r = 0.986–0.998), and the difference biases ranged 0.1–1.9 mmol/mol. In the long mode, only one variant had a difference bias exceeding 14 % [10 % (%NGSP)].

Conclusion

The two analysis modes of GR01 were fast and had high accuracy and reproducibility, indicating their utility for routine clinical use in measuring HbA_1c samples with Hb-Vars.

Objectives

Human chorionic gonadotropin (hCG) levels are essential for the management of trophoblastic diseases. This study aimed to compare the sensitivities and relationships of two hCG measurement methods (total hCG and the free β-subunit of hCG) in managing gestational trophoblastic disease (GTD).

Design and Methods

We analyzed data from patients treated for GTD at Chiba University Hospital between 2008 and 2019. We focused on cases where both total hCG (mIU/mL) and the free β-subunit of hCG (ng/mL) were measured on the same day.

Results

Out of 80 patients (mean age 38.9 ± 11.7 years) and 158 measurements, 26 had values below the sensitivity threshold for both tests. Fifty-nine measurements were positive for total hCG but below the sensitivity threshold for the free β-subunit of hCG, whereas only two showed the opposite. Seventy-one measurements were positive for both total hCG and the free β-subunit of hCG. There was a significant correlation between total hCG and the free β-subunit of hCG with both positive values, (r = 0.94, p < 0.001; Spearman's correlation test). Of the 85 measurements with undetectable free β-subunit levels, 26 also had undetectable total hCG levels. However, total hCG was detectable in 59 patients from these cases, with a median value (interquartile range) of 2.9 (1.75–4.9) mIU/mL.

Conclusions

In the management of GTD, the use of the free β-subunit system alone cannot be recommended.

Objective

Nucleic acid testing can accurately and rapidly identify the presence of pathogenic bacteria. In this study, we analyzed respiratory pathogenic bacteria nucleic acids by LAMP (Loop-mediated isothermal amplification) to clarify the clinical application in patients with bacterial pulmonary infections.

Methods

Clinical data and specimens were collected from 99 patients with bacterial pulmonary infections from June 2021 to April 2023. We compared the differences between nucleic acid detection of LAMP and sputum culture. The correlation between inflammation manifestations of pulmonary imaging and the nucleic acid detection of LAMP was compared and analyzed. And the relationship between LAMP and blood inflammatory markers were analyzed.

Results

The positive rate of LAMP using sputum specimens was significantly higher than that of sputum culture (P < 0.05). Pathogenic bacteria in sputum samples are more likely to be detected by LAMP in patients with inflammatory on lung imaging examination. The coincidence rate of elevated PCT and CRP expression with positive LAMP results were 83.87 % and 88.71 %, respectively. Moreover, PCT, CRP and WBC were significantly higher in LAMP positive group than those in negative group (P < 0.05).

Conclusion

Nucleic acid testing of sputum specimens for pathogenic bacteria by LAMP on the basis of imaging examination can provide a rapid and accurate experimental basis for clinical diagnosis of bacterial pulmonary infections.