Practical Laboratory Medicine最新文献

Introduction

Sexually transmitted infections (STIs) are among the most common infectious diseases worldwide, often leading to coinfections. Timely detection of genital tract pathogens in at-risk populations is crucial for preventing STIs. We evaluated the NAP-Fluo Cycler System, an innovative microfluidic nucleic acid detection platform, for its ability to simultaneously identify Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Ureaplasma urealyticum (UU), Mycoplasma genitalium (MG), and Mycoplasma hominis (MH) in urethral or cervical secretions.

Materials and methods

The limits of detection (LODs), repeatability, specificity, and interference resistance of the system were evaluated using standard strains, a panel of 24 pathogens, and seven interferents. We used the system to analyze 302 clinical samples and compared the results with those of five approved commercial reference kits.

Results

The system achieved LODs of 500 IFU/mL, 500 CFU/mL, and 500 CCU/mL for CT, NG, and UU/MG/MH, respectively, demonstrating high stability (coefficient of variation <1.1 %), specificity, and resistance to interference. Among 302 clinical samples, 237 tested positive with single, dual, and triple infection rates of 35.6 %, 16.2 %, and 3.0 %, respectively. The reference kits detected 138 positive samples. The concordance rates with commercial reference kits were 100 % for UU, NG, and MH; 94.85 % for CT; and 80.00 % for MG.

Conclusions

This system offers a streamlined, rapid, and multiplex detection method that reduces testing time and complexity. Although it performs well with pure strains, it has limitations when using clinical samples of CT and MG, suggesting the need for further refinement before its widespread use in the clinic.

Prader-Willi syndrome (PWS) is a complex genetic disorder caused by lack of expression of genes on the paternally inherited chromosome 15q11.2-q13 region, known as the Prader Willi critical region. Nutritional clinical manifestations change with age and are described in four different phases. The phases span both extremes of the nutritional spectrum, beginning with an infant with poor sucking reflexes and failure to thrive then progressing to an adolescent who may have hyperphagia and be at risk for obesity. The phenotype is likely due to hypothalamic dysfunction due to genetic changes in the Prader Willi critical region. Researchers are examining the pathological mechanisms that determine the disease course.

Background

Pulmonary embolism (PE) poses a significant challenge in diagnosis and treatment, particularly in high-risk patient populations such as those hospitalized for orthopedic reasons. This study explores the predictive and diagnostic potential of laboratory parameters in identifying PE among orthopedic patients.

Objectives

The purpose of this study was to determine whether selected (inexpensive and readily available) laboratory parameters and their coefficients can be used to diagnose pulmonary embolism and whether they are applicable in predicting its occurrence.

Material and methods

Selected laboratory parameters were determined twice in 276 hospitalized orthopedic patients with suspected PE: PLT, MPV, NEU, LYM, D-dimer, troponin I, age-adjusted D-dimer and their coefficients. Depending on the angio-CT results, patients were divided into groups. Selected popular laboratory coefficients were calculated and statistically analyzed. Optimal cutoff points were determined for the above laboratory tests and ROC curves were plotted.

Results

D-dimer/troponin I [p = 0.008], D-dimer [p = 0.001], age-adjusted D-dimer [p = 0.007], NLR/D-dimer [p = 0.005] and PLR [p = 0.021] are statistically significant predictors of PE. D-dimer/troponin I [p < 0.001], troponin I [p = 0.005] and age-adjusted D-dimer [p = 0.001] correlated with the diagnosis of PE after the onset of clinical symptoms.

Conclusions

In the context of orthopedic patients, cost-effective laboratory parameters, particularly the D-dimer/troponin I ratio and age-adjusted D-dimer, exhibit considerable potential in predicting and diagnosing PE. These findings suggest that combining readily available laboratory tests with clinical observation can offer a viable and cost-effective diagnostic alternative, especially in resource-constrained settings. Further studies with larger and diverse patient populations are recommended to validate these results.

a) Objectives

Dopamine is known to cause negative interference on enzymatic creatinine measurement. However, its effect on the Jaffe reaction, and its concentration required to interfere with enzymatic reactions, remain uncertain. This study was designed to study the interference of stable dopamine infusion on Jaffe and enzymatic creatinine assays, as well as the effect of dopamine infusion drip arm contamination on both creatinine assays.

b) Design and Methods

For the first part of the study, dopamine was spiked into pooled plasma samples at different concentrations to mimic the scenario of patients on dopamine infusion at an infusion rate between 2 and 20 μg/kg/min. For the second part, dopamine preparation of 2 g/L (same as the preparation used clinically) was mixed with pooled plasma samples at different proportions to mimic drip arm contamination. Creatinine concentrations were measured using Jaffe and enzymatic reactions.

c) Results

The first part showed that creatinine measurements were not interfered by dopamine infusion at an infusion rate between 2 and 20 μg/kg/min. The second part showed that dopamine could negatively interfere with enzymatic creatinine assays, even with minute drip arm contamination. The effect on the Jaffe reaction was less significant.

d) Discussion

Creatinine concentration could be reliably measured by Jaffe or enzymatic reactions if samples are from venous access sites other than the site of dopamine infusion. When dopamine interference on enzymatic creatinine assays is suspected, using the Jaffe reaction to cross-check may provide additional useful information.

Background

The plasma concentration of 5-Fluorouracil (5-FU) is affected by numerous factors, thereby limiting its efficacy. The current therapeutic regimen's doses based on body surface area (BSA) are linked to increased toxicity and sometimes inadequate drug exposure.

Aim and objectives

The study aims to develop an in-vitro assay to monitor 5-Fluorouracil's therapeutic efficacy in cancer patients' blood samples, focusing on pharmacokinetics to improve therapy precision.

Materials and methods

Drug levels were determined from standards, quality controls, and experimental samples using protein precipitation, liquid-liquid extraction, and separation using a C18 analytical column with an isocratic program.

Result

In EXP-1A, the mean concentration of 5-Fluorouracil was 1.15 μg/ml; in EXP-1B, it was 1.16 μg/ml, while in EXP-1C, the mean concentration was 0.9 μg/ml. The percentage difference in mean 5-Fluorouracil concentration between the experiment sample containing a DPD inactivator and EXP-1C (without a DPD inactivator) was 21.5 % higher for EXP-1A and 0.68 % higher for EXP-1B. In the second phase of the experiment, the overall stability of 5-Fluorouracil in samples containing a DPD inactivator was 24.5 % superior compared to samples without a DPD inactivator.

Conclusion

A modified extraction technique has been developed to accurately measure 5-Flourouracil concentration in blood, preserving its stability and concentration by adding a DPD inactivator.

Insulin degrading enzyme (IDE) plays a critical role in degrading insulin and beta-forming proteins, implicating its significance as a biomarker in metabolic dysfunction and neurocognitive disorders, including Alzheimer's disease (AD). Understanding the impact of pre-analytic conditions of in vitro IDE levels is imperative for reliable biomarker assessment. This study explored the influence of freeze-thaw cycles, storage temperature, and storage time on IDE levels in human serum.

Serum samples from seven healthy volunteers were subjected to various storage conditions, including refrigeration (4 °C) and freezing (−20 °C and −80 °C) for 24 h and six months, with differing freeze-thaw cycles. In vitro IDE levels were measured at 24 h and after 6 months using ELISA.

Results indicate that while short-term storage at either −20 °C or −80 °C yielded similar IDE levels, prolonged storage and multiple freeze-thaw cycles significantly impacted IDE stability, with colder temperatures exhibiting better preservation.

Although further research with larger cohorts and longer storage time is warranted to establish clinical significance, our study suggests preferential use of unthawed samples or consistent freeze-thaw conditions for accurate IDE assessment. Thus, optimizing sample storage conditions is paramount for reliable IDE biomarker analysis in clinical and research settings.

This study aims to investigate the correlation between plasma fat-soluble vitamin levels and blood lipid in elderly patients with coronary heart disease (CHD). A total of 120 participants were enrolled, including 60 CHD patients and 60 controls without CHD. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to quantify plasma levels of vitamins A, D₃, E, and K. Data analysis was conducted using the statistical analysis system module of MetaboAnalyst 5.0. The CHD group showed significantly higher levels of plasma total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C) but not high-density lipoprotein cholesterol (HDL-C) compared to controls. The CHD group exhibited significantly higher plasma levels of VA and VE, positively correlating with TC, TG, and LDL-C. After adjusted by TG levels, the CHD group had significantly lower plasma levels of VA and VE, negatively correlating with TC, TG, and LDL-C. The CHD group also had significantly lower concentrations of VD₃, independent of TG modification, compared to controls. VD₃ negatively correlated with TC, TG, and LDL-C. Elderly individuals with CHD display abnormal blood lipid metabolism, and fat-soluble vitamins adjusted by TG levels can more accurately and timely response to implicit fat-soluble vitamins deficiency in CHD patients.

Background

Most glycated hemoglobin A1c (HbA1c) analytical reagents used were obtained from the analyzer's manufacturer. However, clinical laboratories need more choices for HbA1c analytical reagents to overcome the limitations of dedicated reagents for special analyzers. We developed new mobile phase buffers as HbA1c diagnostic reagents and evaluated their analytical performance for the HbA1c assay.

Methods

Different mobile phase buffers used as HbA1c diagnostic reagents were prepared using different concentrations of sodium salts. According to the Clinical and Laboratory Standards Institute (CLSI) recommendation guidelines, the analytical performances of the newly developed mobile phase buffers were evaluated on an ARKRAY HA-8160 Analyzer. Both quality controls and clinical blood samples were used in these experiments. To assess the quality of the newly developed mobile phase buffers, precision, accuracy, linearity, carryover, interference, bias, correlation with commercial reagents, and stability were analyzed.

Results

The CVs of intra-assay precision and interassay precision of quality control and clinical.

There were fewer than 1.00 % blood sample assays using the newly developed mobile phase buffer. The RDs of accuracy were less than 1.00 %. Linearity: R² = 0.9998 in the concentration range of 4.40%–17.30 %. Carryover: 0.00 %. Reagent comparison revealed that the Pearson regression equation was Y = 0.9884x+0.05692 (R² = 0.9977), and the Bland-Altman mean difference was −0.02650 % (CI: −0.2121 %–0.1591 %) between the two analytical reagents. Stability was also acceptable within 12 months. This mobile phase buffer showed good anti-interference ability.

Conclusion

The newly developed mobile phase buffers demonstrated good analytical performance and were suitable for clinical HbA1c assays on an ARKRAY HA-8160 Analyzer.

Background

Pandy's test is used to assess the globulin level in cerebrospinal fluid (CSF). As a semi-quantitative manual method, the practicality and clinical value of Pandy's test has been challenged.

Objective

We tend to summarize the relationship between CSF total protein (CSF-TP) quantification and Pandy's results, providing a formula to estimate Pandy's results merely by CSF-TP value.

Methods

This retrospective study involved 1090 cases hospitalized in Huashan Hospital during 1/1/2023 to 20/4/2023. All samples were divided into six group based on their Pandy's results. Their corresponding CSF-TP quantitative results were subsequently analyzed and summarized. Another 364 patients were also gathered for verification.

Results

The turbidity of samples won't affect examiners'ocular inspection and interpretation of Pandy's tests in positive groups. The results of Pandy's tests can be deduced based on CSF-TP quantitative results according to following rules: CSF-TP quantitative results 0–614 mg/L for Pandy negative (−), 615–1322 mg/L for extremely weak positive (±), 1323–2953 mg/L for weak positive (1+), 2954–6561 mg/L for medium positive results (2+), 6562–13007 mg/L for strong positive results (3+) and CSF-TP results >13007 for strongest positive (4+). The quantitative range above was experimentally verified as effective and correct by calculating the agreement rate through another 364 samples and the R ratio of each Pandy group was greater than 90 %.

Conclusion

There is an excellent correlation between CSF-TP and Pandy's test. Therefore, CSF-TP quantification test through PROT Slides can be used to infer the results of Pandy's test to accelerate the abolish of this traditional manual test.

Acquired methemoglobinemia, predominantly due to oxidizing medications occurs when heme iron in hemoglobin is oxidized from ferrous to ferric ion and binds oxygen irreversibly leading to functional anemia, cyanosis, and tissue hypoxia. We report a case of a 60-year-old man with multiple comorbidities who was diagnosed with coronavirus disease 2019 (COVID-19) and developed methemoglobinemia after consumption of prescribed supplements. He presented with dyspnea and cyanosis. An oxygen saturation gap with characteristic chocolate-brown arterial blood indicated methemoglobinemia. Outsourced methemoglobin (MetHb) was increased at 9.0%. Despite aggressive intervention, he succumbed to his illness. In this case, we discuss the pathophysiology of why some individuals, especially the elderly with COVID-19 are more susceptible to develop methemoglobinemia after possibly being exposed to oxidizing agents. Laboratory methods for assessing oxygen saturation, including pulse oximetry, arterial blood gas and co-oximetry are examined in relation to this case. The importance of considering a diagnosis of methemoglobinemia based on clinical and biochemical findings although MetHb assay or co-oximetry are not readily available is also emphasized.