Clinical chemistry and laboratory medicine最新文献

Objectives: The Kappa Index has proven its diagnostic value for multiple sclerosis (MS), while its prognostic potential remains to be fully explored. The objective of this study is thus to investigate the value of the Kappa Index at disease onset in predicting disease activity and high-efficacy therapy (HET) initiation.

Methods: We enrolled MS patients with available Kappa Index values at disease onset and a follow-up of at least two years. Primary outcome was the time to loss of NEDA3 (no evidence of disease activity-3) defined as the absence of relapses, MRI activity, and disability progression. Secondary outcome was the time to HET initiation.

Results: Of 120 enrolled patients (36 M, 84 F, mean age: 35 ± 11 years), NEDA3 loss occurred in 89 (74 %) by the end of the follow-up period. A total of 98 (82 %) initiated a moderate efficacy therapy (MET); of these, 34 (28 %) transitioned to a HET during follow-up. Kappa Index values above the maximally selected log-rank statistic-derived cut-off of 38 were independent risk factors for NEDA3 loss (HR 1.75, 95 % CI: 1.09-2.80, p=0.021) and HET initiation (3.25, 95 % CI: 1.54-6.87, p=0.002) and also independently predicted HET following MET failure (2.54, 95 % CI: 1.17-5.51, p=0.018).

Conclusions: Elevated Kappa Index values at diagnosis predict disease activity, MET failure and HET initiation and may be a valuable adjunctive tool in identifying patients in need of prompt HET initiation.

Objectives: Free triiodothyronine (FT3) and free thyroxine (FT4) are important diagnostic markers for assessing thyroid function. However, their accurate quantification remains challenging due to low serum concentrations. Significant variability exists among current assay methods for measuring FT3 and FT4. This study aims to establish a candidate Reference Measurement Procedure (cRMP) for simultaneous quantification of serum FT3 and FT4 based on isotope-dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) technology.

Methods: A convenient and reusable equilibrium dialysis (ED) device was utilized to separate free thyroid hormones from their protein-bound counterparts in serum. Key dialysis parameters, including temperature, pH, membrane type, and duration, were optimized to ensure consistent and reliable performance. The dialysate containing FT3 and FT4 was directly quantified by ID-LC-MS/MS. The method underwent systematic validation, comparative analysis with existing assays, and a comprehensive uncertainty assessment.

Results: The developed cRMP demonstrated limits of quantification (LoQ) of 1.54 pmol/L for FT3 and 3.22 pmol/L for FT4, and with an imprecision of less than 3 %. No interference from endogenous analogs was observed, and the method showed good consistency in interlaboratory comparison. In contrast, chemiluminescent immunoassay results exhibited poor agreement with and the cRMP.

Conclusions: This study developed a highly precise, accurate, specific, and sensitive ID-LC-MS/MS-based cRMP for the simultaneous measurement of FT3 and FT4 in human serum. This method provides a reliable tool for standardizing routine thyroid function tests.

Objectives: Prognostication in patients with severe acute brain injury (SABI) in the Intensive Care Unit (ICU) is complex, often requiring early decisions on life-sustaining therapy. Serum biomarkers such as neurofilament light (NFL), glial fibrillary acidic protein (GFAP) and neuron specific enolase (NSE) may aid in predicting outcomes. This study investigated the association between biomarker concentrations and hospital mortality in ICU patients with SABI.

Methods: In this prospective multi-center study, 103 adult ICU patients with SABI were enrolled within 24 h of injury. Serum concentrations (NFL, GFAP, NSE) were measured at 24 h, 72 h, 7 days, and 14 days post-injury. Biomarker concentrations between hospital survivors and non-survivors were compared using a linear mixed-effects model and ROC curves.

Results: GFAP concentrations peaked on day 1, while NSE and NFL concentrations peaked on day 14. Higher concentrations were observed in non-survivors for all biomarkers on day 3, a 1,4 fold increase for NSE (p=0.034) and approximately 2-fold increase for GFAP (p=0.041) and NFL (p=0.018). Distinct temporal patterns were observed for all biomarkers, although biomarker trajectories did not significantly differ between survivors and non-survivors. Prognostic accuracy was moderate when biomarkers were combined with established mortality predictors (AUC 0.749) on day 3.

Conclusions: NSE, GFAP and NFL show distinct temporal trajectories in SABI patients. Concentrations were higher in non-survivors during the early phase of admission. While individual biomarkers showed limited prognostic accuracy, in combination with other predictors mortality prediction improved. Serum biomarkers may still be valuable in a multimodal prognostication framework for SABI patients.

Objectives: Vitamin K homologues are essential to human health, and their concentrations in biological samples serve as valuable diagnostic biomarkers. This study was aimed to develop a method for determining vitamins K1 (phylloquinone, VK1) and K2 (menaquinone, MK-4) in human serum. The proposed method was validated and applied to the serum of a cohort of 20 Russian individuals.

Methods: High-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) was used to analyse the content of VK1 and MK-4 in serum. Atmospheric pressure chemical ionisation (APCI) in negative mode was applied to ionise VK1 and MK-4. Protein precipitation and solid-phase extraction (SPE) on polystyrene-divinylbenzene resin were combined to isolate and preconcentrate the analytes from serum.

Results: The HPLC-MSMS method was developed and validated for the determination of vitamins VK1 and MK-4 in human serum. The method demonstrated a lower limit of quantification (LLOQ) of 0.05 μg/L, with more than 71 % recoveries and precision within 17 %. To demonstrate the applicability of the method to real samples, serum from 20 healthy adults was analyzed. VK1 was detected in four individuals (0.094-0.96 μg/L), whereas MK-4 concentrations were below 0.22 μg/L in all cases.

Conclusions: The validated HPLC-MS/MS workflow provides a reliable and sensitive approach for the quantification of VK1 and MK-4 in minimal serum volumes. The method demonstrates robustness, reproducibility, and suitability for large-scale analytical applications. The proposed LC-MS/MS protocol successfully applied to native human serum samples, illustrating its applicability for future clinical and biochemical studies involving vitamin K.