Simultaneous determination of inflammatory factors SAA and LTF based on stable element labeling and inductively coupled plasma mass spectrometry to aid in the diagnosis of infection.

OBJECTIVE: The clinical value of Serum amyloid A (SAA) and Lactoferrin (LTF) has received significant attention, but their detection methods are inadequate, which limits their application. This study aims to develop a dual detection method based on stable element labeling strategies and inductively coupled plasma mass spectrometry (ICP-MS) for SAA/LTF and to assess whether it can be widely used in clinical practice. METHODS: A duplex immunoassay system based on sandwich method was constructed. After optimization, methodological evaluation was performed with the guidelines of Clinical Laboratory Standards Institute (CLSI). Finally, 131 plasma samples were collected to analyze whether the new method is suitable for clinical detection. RESULTS: The LoB, LLoQ, ULoQ, and linear range of the assay were 1.09 ng/mL, 3 ng/mL, 1500 ng/mL, 3-1500 ng/mL for SAA and 0.85 ng/mL, 2 ng/mL, 1200 ng/mL, 2-1200 ng/mL for LTF respectively. The recovery rates were 95.01% to 106.26%, the intra-batch precision of low, intermediate, and high-level samples was <8%, and the inter-batch of them was <11%, the deviation of interference test results was less than±10%. The Area Under the Curve (AUC) was 0.9809 for SAA, 0.8599 for LTF, and 0.9986 for combination. CONCLUSION: The quantitative duplex immunoassay for SAA/LTF has high accuracy, good precision, and high specificity, which meets the clinical testing requirements and can be widely used in clinical practice.

The blood monocyte to high density lipoprotein cholesterol ratio (MHR) is a possible marker of carotid artery plaque.

BACKGROUND: MHR is the ratio of monocyte to high-density lipoprotein cholesterol (HDL-C). It has been reported that MHR changes are associated with cardiovascular and cerebrovascular disease. Carotid plaque is a common vascular lesion of the carotid artery and is a manifestation of atherogenesis. This study investigated the relationships between the MHR and the incidence of carotid plaques. METHODS: The data of 3848 physical examiners were analyzed for retrospective analysis, which included 1428 patients with noncarotid plaque, 1133 patients with single carotid plaque, and 1287 patients with bilateral or multiple carotid plaques. Statistical analysis was performed on SPSS 22.0 0 software and statistical software R and its GAM package. RESULTS: The difference was statistically significant in the levels of MHR, body mass index (BMI), high-sensitivity C-reactive protein (hs-CRP), blood lipids (HDL-C, low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triglyceride (Tg)), blood glucose (Glu), hemoglobin A1c (HbA1c), renal function (urea, creatinine (Crea)), estimated glomerular filtration rate (eGFR), and uric acid (Ua) in the carotid plaque groups (P < 0.001, respectively). There was no significant difference between the sex (P = 0.635) and age (P = 0.063) in the different groups. MHR levels were positively correlated with BMI (r = 0.364, P < 0.001), hs-CRP (r = 0.320, P < 0.001), Tg (r = 0.417, P < 0.001), Crea (r = 0.323, P < 0.001), eGFR (r = - 0.248, P < 0.001), Ua (r = 0.383, P < 0.001) and HbA1c (r = 0.197, P < 0.001). Levels of TC, Glu, and urea were slightly correlated with the MHR level (r = - 0.150, P < 0.001; r = 0.187, P < 0.001; r = 0.137, P < 0.001, respectively). The MHR level increased with elevated severity of carotid plaque in subjects without hypertension or diabetes (P < 0.001). In adjusted models, with the rise of MHR level, the probability of occurrence of carotid plaque had a 1.871-fold (95% CI: 1.015-3.450, P = 0.045) increase; the probability of multiple occurrences of carotid plaques had a 2.896-fold (95% CI: 1.415-5.928, P < 0.001) increase. The GAM curve showed a nonlinear correlation between the normalized MHR and the probability of carotid plaque occurrence. CONCLUSIONS: MHR could be used as a possible marker for plaque formation and severity.

Reference Intervals and Regularity Analysis of Biochemical Makers in 3-Year-Old Children.

BACKGROUND: The reference intervals of biochemical markers were significantly affected by age and gender, especially in minors. In recent years, many provinces and regions in China had established reference intervals for children's hematological indicators. Without considering the instruments and reagents, the reference interval will also be affected by the region, economic development, eating habits, and other factors. Therefore, the reference interval of any hematological indicators is not necessarily a fixed range, it changes with certain factors. In our study, we analyzed the changes of biochemical markers in different serum total Ca and 25-OH-D concentrations, and established the reference intervals of biochemical markers in 3-year-old children, explored the change trend of biochemical markers with different serum total Ca and 25-OH-D concentration. METHODS: Data was collected from 226 cases of 3-year-old children for biochemical markers, in the Chinese PLA General Hospital in August 2015. The data were divided into a high-level group (serum total Ca > 2.63 mmol/L and 25-OH-D > 40.81 ng/mL) and a low-level group (serum total Ca < 2.54 mmol/L and 25-OH-D < 32.64 ng/mL) according to serum total Ca and 25-OH-D levels for comparison. The change trend of biochemical markers was compared according to serum total Ca and 25-OH-D level. RESULTS: The Glu levels in boys were significantly higher than that in girls, but CHO and LDL-C in girls were significantly higher than that in boys. The reference intervals of ATL (5.6 - 22.1 U/L), ALB (44.8 - 55.2 g/L), TP (62.7 - 83.1 g/L), ALP (154.4 - 379.7 U/L), GGT (7.2 - 15.9 U/L), Glu (boys: 4.08 - 5.91 mmol/L; girls: 4.05 - 5.37 mmol/L), UREA (2.7 - 6.3 mmol/L), CREA (26.4 - 46.8 µmol/L), UA (182.4 - 400.2 µmol/L), TG (0.43 - 1.67 mmol/L), CHO (boys: 3.19 - 5.96 mmol/L; girls: 3.03 - 6.51 mmol/L), HDL-C (0.98 - 2.24 mmol/L), LDL-C (boys: 1.30 - 3.64 mmol/L; girls: 1.24 - 4.27 mmol/L), total Ca (2.34 - 2.85 mmol/L), PHOS (1.38 - 2.06 mmol/L), Mg (0.83 - 1.06 mmol/L), osteocalcin (41.64 - 91.92 ng/mL), PTH (12.08 - 43.06 pg/mL), 25-OH-D (19.66 - 56.37 ng/mL), ß-CrossLaps (0.82 - 1.88 ng/mL), TP1NP (357.9 - 1025.7 µg/L) were established. ALT, TP, ALB, GGT, Glu, CHO, HDL-C, LDL-C, UREA, CREA, PHOS, Mg, and ALP in high level group were significantly higher than those in low level group. There was no significant difference in TG, UA, TP1NP, osteocalcin, PTH and ß-CrossLaps between high level group and low-level group. With the increase of serum total Ca and 25-OH-D levels, most of the biochemical markers had a gradually increasing trend. However, biochemical markers of bone (TP1NP, osteocalcin, PTH, ß-CrossLaps) showed different trends. CONCLUSIONS: This study established the reference intervals of biochemical markers of 3-year-old children. The changes of serum total Ca and 25-OH-D levels in children reflected the changes of glucose and lipid metabolism, liver and kidney function markers, and indirectly reflected the growth and development of children and various organ functions. Maintaining high levels of serum total Ca and 25-OH-D can promote the growth and development of children.

Evaluation of an Element-Tagged Duplex Immunoassay Coupled with Inductively Coupled Plasma Mass Spectrometry Detection: A Further Study for the Application of the New Assay in Clinical Laboratory.

BACKGROUND: Element-tagged immunoassay coupled with inductively coupled plasma mass spectrometry (ICP-MS) detection has the potential to revolutionize immunoassay analysis for multiplex detection. However, a further study referring to the standard evaluation and clinical sample verification is needed to ensure its reliability for simultaneous analysis in clinical laboratories. METHODS: Carcinoembryonic antigen (CEA) and α-fetoprotein (AFP) were chosen for the duplex immunoassay. The performance of the assay was evaluated according to guidelines from the Clinical and Laboratory Standards Institute (CLSI). Moreover, reference intervals (RIs) of CEA and AFP were established. At last, 329 clinical samples were analyzed by the proposed method and results were compared with those obtained with electrochemiluminescent immunoassay (ECLIA) method. RESULTS: The measurement range of the assay was 2-940 ng/mL for CEA and 1.5-1000 ng/mL for AFP, with a detection limit of 0.94 ng/mL and 0.34 ng/mL, respectively. The inter-assay and intra-assay imprecision were all less than 6.58% and 10.62%, respectively. The RI of CEA and AFP was 0-3.84 ng/mL and 0-9.94 ng/mL, respectively. Regarding to clinical sample detection, no significant difference was observed between the proposed duplex assay and the ECLIA method. CONCLUSIONS: The ICP-MS-based duplex immunoassay was successfully developed and the analytical performance fully proved clinical applicability. Well, this could be different with other analytes.

Simultaneous determination of gastric cancer biomarkers pepsinogen PGI/PGII using element tagged immunoassay coupled with inductively coupled plasma mass spectrometry detection.

OBJECTIVES: In this study, a new immunoassay for the simultaneous determination of pepsinogen I (PGI) and pepsinogen II (PGII) in serum based on element labeling strategy coupled with inductively coupled plasma mass spectrometry (ICP-MS) detection was proposed. METHODS: The sandwich-type immunoassay was used to simultaneously detect PGI and PGII in serum. PGI and PGII were captured by anti-PGI and anti-PGII antibody immobilized on the magnetic beads and then banded with Eu3+ labeled anti-PGI detection antibody and Sm3+ labeled anti-PGII detection antibody, followed by ICP-MS detection. RESULTS: The linear correlation coefficient (R2 ) of PGI and PGII standard curves was .9938 and .9911, with the dynamic range of 0-200 ng/mL and 0-60 ng/mL, respectively. The limit of detection for PGI and PGII was 1.8 ng/mL and 0.3 ng/mL, respectively. The average recovery was 101.41% ± 6.74% for PGI and 101.47% ± 4.20% for PGII. Good correlations were obtained between the proposed method and CLIA (r = .9588 for PGI, r = .9853 for PGII). CONCLUSIONS: We established a mass spectrometry-based immunoassay for the simultaneous detection of PGI and PGII in a single analysis. The element tagged immunoassay coupled with ICP-MS detection has high sensitivity, accuracy, and specificity in clinical serum sample analysis.

A preliminary study for the establishment of a reference interval for vitamin B12 in China after performance verification of a second-generation ECLIA kit.

BACKGROUND: The second-generation electrochemiluminescence immunoassay (ECLIA) kit of vitamin B12 is widely used in clinical laboratories, and the establishment of a reference interval (RI) is essential to provide the basis for clinical monitoring. The purpose of this study was to establish a laboratory RI for vitamin B12 in China and at the same time verify the method performance of the second-generation kit. METHODS: The verification of the method performance was conducted according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Based on these guidelines, a total of 580 serum samples were collected, and 391 serum samples were used for the establishment of the RI according to CLSI guidelines. The subjects were grouped by sex and age. The age groups were as follows: 21-40, 41-60, and 61-80 years. The RI was defined by nonparametric 2.5th and 97.5th percentile intervals. RESULTS: The performance of the second-generation kit of vitamin B12 from the Roche Cobas E602 system was in compliance with laboratory requirements. Serum vitamin B12 levels conformed to a non-Gaussian distribution. Harris-Boyd's test did not indicate partitioning for different age and gender group. Besides, there was no significant difference between different age groups (P = .07) and gender groups (P = .2002). The RI for healthy Chinese adults (aged 21-80 years) calculated by the nonparametric method was 250.8-957.1 pg/mL. CONCLUSIONS: The reference range of vitamin B12 was established, which provided a theoretical basis for the clinical application and monitoring of vitamin B12 detection.

Development and evaluation of an element-tagged immunoassay coupled with inductively coupled plasma mass spectrometry detection: can we apply the new assay in the clinical laboratory?

Introduction Element-tagged immunoassay coupled with inductively coupled plasma-mass spectrometry (ICP-MS) detection has the potential to revolutionize immunoassay analysis in clinical detection; however, a systematic evaluation with the standard guidelines of the assay is needed to ensure its performance meets the requirements of the clinical laboratory. Methods Carcinoembryonic antigen (CEA) was chosen for analysis using the proposed method. A systematic evaluation of the proposed assay was carried out according to the Clinical and Laboratory Standards Institute (CLSI). The 469 clinical samples were analyzed using the new method and compared with the electrochemiluminescent immunoassay (ECLIA) method. Results The measurement range of the assay was 1-900 ng/mL, with a detection limit of 0.83 ng/mL. The inter-assay and intra-assay imprecision were 4.67% and 5.38% with high concentration samples, and 9.27% and 17.64% with low concentration samples, respectively. The cross-reactivity (%) for different antigens was less than 0.05%, and the recovery was between 94% and 108%. Percentage deviation of all the dilutions was less than 12.5% during linearity estimation. The interference bias caused by different substances was less than 10%. The reference interval of the assay was 0-4.442 ng/mL. Comparison with the commercial ECLIA method for clinical sample detection, the proposed method showed a correlation of 0.9878 and no significant differences between the methods were observed (p = 0.6666). Conclusions The ICP-MS based immunoassay was successfully developed, and the analytical performance of the assay met the requirements of the CLSI, which fully proved the clinical transferability and application of the new method.

The predictive value of selected serum microRNAs for acute GVHD by TaqMan MicroRNA arrays.

Currently, the diagnosis of acute graft-versus-host disease (aGVHD) is mainly based on clinical symptoms and biopsy results. This study was designed to further explore new no noninvasive biomarkers for aGVHD prediction/diagnosis. We profiled miRNAs in serum pools from patients with aGVHD (grades II-IV) (n = 9) and non-aGVHD controls (n = 9) by real-time qPCR-based TaqMan MicroRNA arrays. Then, predictive models were established using related miRNAs (n = 38) and verified by a double-blind trial (n = 54). We found that miR-411 was significantly down regulated when aGVHD developed and recovered when aGVHD was controlled, which demonstrated that miR-411 has potential as an indicator for aGVHD monitoring. We developed and validated a predictive model and a diagnostic model for aGVHD. The predictive model included two miRNAs (miR-26b and miR-374a), which could predict an increased risk for aGVHD 1 or 2 weeks in advance, with an AUC, Positive Predictive Value (PPV), and Negative Predictive Value (NPV) of 0.722, 76.19 %, and 69.70 %, respectively. The diagnostic model included three miRNAs (miR-28-5p, miR-489, and miR-671-3p) with an AUC, PPV, and NPV of 0.841, 85.71 % and 83.33 %, respectively. Our results show that circulating miRNAs (miR-26b and miR-374a, miR-28-5p, miR-489 and miR-671-3p) may serve as biomarkers for the prediction and diagnosis of grades II-IV aGVHD.