Practical Laboratory Medicine最新文献

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.

Objectives

The clamshell isothermal nucleic acid amplification analyzer RTisochip-S, a next-generation instrument featuring improved structural design, enhanced functional integration, reduced cost, and increased portability, was assessed for its suitability in clinical respiratory pathogens detection.

Methods

The certificated detection kit for lower respiratory tract bacteria (LRTB-kit) was applied to evaluate the performance of RTisochip-S via sensitivity, specificity, and repeatability analysis. The clinical specimens, including 51 sputum specimens and 10 bronchoalveolar lavage fluid specimens, were simultaneously detected on both RTisochip-S and a certificated reference instrument (RTisochip-A) to assess the consistency.

Results

The results indicated that RTisochip-S fulfills the sensitivity, specificity, and repeatability requirements of the LRTB-Kit, and the results of clinical specimens on the two instruments were consistent.

Conclusions

RTisochip-S is satisfying the clinical detection of respiratory pathogens while enhancing portability and compactness, making it more well-suited for point-of-care testing (POCT) applications.

Objectives

Salivary cortisol reflects the biologically active form of serum cortisol, offering a noninvasive evaluation method for the diurnal rhythm of the hypothalamic-pituitary-adrenal (HPA) axis. While liquid chromatography-tandem mass spectrometry (LC-MS/MS) is known for its specificity, immunoassays (IA) are commonly used because of their simplicity. This study aimed to assess the performance of salivary cortisol measurement using both IA and LC-MS/MS in comparison to serum-free cortisol measurement.

Methods

Assay results for 188 saliva and 94 serum samples from 47 participants were analyzed. Salivary samples collected at different time points were analyzed using IA and LC-MS/MS. Serum samples were analyzed for cortisol, cortisol-binding globulin, and free cortisol. The statistical analyses included correlations and method comparisons.

Results

The diurnal salivary cortisol profiles exhibited a comparable circadian rhythm pattern; however, the concentrations measured using IA were consistently higher than those measured using LC-MS/MS. The correlation analysis revealed robust associations among salivary cortisol (IA), salivary cortisol (LC-MS/MS), and serum-free cortisol levels (LC-MS/MS). However, the method comparison revealed a systematic bias between IA and LC-MS/MS in salivary cortisol measurement.

Conclusions

This study contributes to the ongoing debate on assay techniques by affirming the suitability of IA and LC-MS/MS for salivary cortisol measurement to assess dynamic changes in HPA axis activity. The identified systematic bias emphasizes the importance of selecting methods based on specific research or clinical requirements.

Objectives

Urinalysis is a first-line test for screening for urinary tract infection. Several devices performing strip and sediment analysis have been introduced. The aim of this study was to compare the performance of Labsan Tricell-1000 and Dirui FUS-2000 automated urine analyzers with manual microscopy.

Methods

463 urine samples were analyzed. Digital image processing and particle recognition automatically display the cells in a flowing sheath fluid mixed monolayer urine sample, take the pictures of particles via digital camera, analyse these pics with a particle recognition software, transfer images of the formed elements to the screen and allow well-trained personnel to select, reclassify or remove them. Manual microscopy was used for comparison.

Results

Agreement between Tricell-100 and manual microscopy was very good for RBC (ϰ = 0.80), and WBC (ϰ = 0.83); good for CaOx (ϰ = 0.69), SEC (ϰ = 0.80), YLC (ϰ = 0.72), HC (0.69) and LC (ϰ = 0.64); moderate for BAC (ϰ = 0.51), APC (ϰ = 0.43) and MT (ϰ = 0.55); fair for GC (ϰ = 0.39) and RTEC (ϰ = 0.32).

Conclusions

Labsan Trion TriCell-1000 demonstrated satisfactory performance and can be used in routine urinalysis. In the case of low counts of RBC, presence of yeast, crystal, casts or cell clumping in urine sediment, characterization of urine particles should be performed by manual microscopy.

Objectives

The aim of this study was to demonstrate the performance and added value of rapid glucose determination in cerebrospinal fluid using a connected glucometer.

Design and Methods

Intra-assay and inter-assay accuracies were calculated using residual clinical samples. Accuracies were measured by comparing the results obtained with the glucometer to those from the central laboratory on a large routine chemistry platform.

Results

The intra-assay coefficients of variation were between 6.1% and 6.2% for low values (18 mg/dL) and between 5.6% and 6.8% for high values (58 mg/dL). The inter-assay coefficients of variation were between 9.4% and 16.3% for the low values (18 mg/dL) and between 5.7% and 8.7% for the high values (pool; ±75 mg/dL). The regression equation by comparison to the central laboratory was y = 4.08 + 0.82 x, with a coefficient of determination (r²) of 0.95.

Conclusions

The measurement of glycorrhachia with a connected glucometer before the analysis in the central laboratory allows a rapid orientation in the deferential diagnosis of a meningitis of viral vs bacterial origin. The response time is fast (6 s) and requires only a small amount of fluid (1.2 μL), which is important in infants, especially since lumbar puncture is an integral part of the investigation of the origin of a fever in this population.