Annals of Clinical Biochemistry最新文献

Purpose: The primary goal was to estimate reference values of parathyroid hormone (PTH) in very low birth weight infants without severe neonatal morbidity. A secondary objective was to assess the relationship between PTH serum levels and selected laboratory markers of bone metabolism.

Methods: Ninety two infants with birth weight less than 1500 g met the inclusion criteria of the study. Serum levels of PTH, 25-hydroxyvitamin-D [25(OH)D], C3-epi-25(OH)D, total calcium, phosphorus, and alkaline phosphatase, and urinary levels of calcium, phosphorus, and creatinine were examined on day 14 and subsequently every 2 weeks until discharge.

Results: Of the total 167 serum samples examined for PTH levels in infants without 25(OH)D deficiency the estimated range was 0.9-11.9 pmol/l (8.5-112.3 pg/mL). During the first month, no statistically significant correlation was observed between PTH level and that of 25(OH)D, C3-epimers of 25(OH)D, S-Ca, S-P, or ALP, nor with urinary excretion of calcium and phosphorus. From the second month of life, there was a moderately significant correlation between PTH and 25(OH)D (Rho = -0.40, P =< .001), between PTH and calcium/creatinine ratio (Rho = -0.56, P = < .001), and between PTH and phosphorus/creatinine ratio (Rho = 0.51, P = < .001).

Conclusions: The physiological range for PTH levels for preterm neonates without 25(OH)D deficiency was estimated as 0.9-11.9 pmol/l (8.5-112.3 pg/mL). It seems that elevation of serum PTH above this range can be considered as hyperparathyroidism in very low birth weight infants.

Background: There is a lack of standardization of reference intervals (RIs) for ferritin across laboratories, particularly for postmenopausal women. Depending on the RI used, there can be more than a 4-fold difference in the upper limit of normal between laboratories, resulting in potential misinterpretation.

Methods: This retrospective study used a large dataset of blood test results from 25,425 healthy participants aged 18 to 97 over a 7-year period. Exclusion criteria were used to screen out individuals with conditions known to affect iron metabolism or raise ferritin as part of the acute phase response. Distributions were assessed using density and Q-Q plots, and age-banded cut-offs were determined. The non-parametric method was used to establish RIs for sex and age bands.

Results: For females, 4 age bands were established (18-39, 40-49, 50-59 and 60+). For males, 2 bands were identified (18-39 and 40+). Performance against a validation dataset, followed by an expansive validation against an inclusive dataset, demonstrated the robustness of the derived RIs.

Conclusion: This study addresses the inconsistency in serum ferritin RIs by presenting intervals based on demographic parameters. This approach can potentially enhance the accuracy of interpreting serum ferritin levels, assisting clinicians in identifying patients requiring further evaluation.

Background: Non-alcoholic fatty liver disease is classified into simple steatosis (SS) and non-alcoholic steatohepatitis (NASH) according to histological findings from liver biopsies. Phosphatidylcholine (PC), the main component of phospholipids in serum lipoproteins, is easily oxidized to phosphatidylcholine hydroperoxide (PC-OOH). Although a lipid composition in the low-density lipoproteins (LDL) from patients with NASH could be abnormal, it remains unclear. Here, to better understand the characteristics of lipids in the LDL from NASH and SS, we compared the composition of PC and PC-OOH species in LDL particles (LDL-PC, LDL-PCOOH) from these patients, then clarified the association between these lipids and NASH severity.

Methods: The serum samples from patients with NASH (female, n = 9) and SS (female, n = 4; male, n = 2) were used for isolation of LDL. Total lipids were extracted from isolated LDL, and the species of PC and PC-OOH were measured using liquid chromatography-mass spectrometry/mass spectrometry.

Results: The sum of LDL-PC and the sum of LDL-PCOOH were significantly higher in NASH than in SS. Several LDL-PC (PC 32:0, 32:1, 32:2, 34:3, 36:2, sum of PC with saturated fatty acyl chains and sum of LDL-PC with polyunsaturated fatty acyl chains) and several LDL-PCOOH (34:2, 36:2, 36:3 and total) were increased significantly with increasing fibrosis score. In particular, a series of LDL-PCOOH were more reflective of the severity of fibrosis score.

Conclusions: LDL-PC and LDL-PCOOH species were strongly correlated with the fibrosis score in NASH, which suggests that abnormal LDL is involved in the development of liver fibrosis.

Background: Clinical laboratories frequently implement the same tests and internal quality control (QC) rules on identical instruments. It is unclear whether individual QC targets for each analyser or ones that are common to all instruments are preferable. This study modelled how common QC targets influence assay error detection before examining their effect on real-world data.

Methods: The effect of variable bias and imprecision on error detection and false rejection rates when using common or individual QC targets on two instruments was simulated. QC data from tests run on two identical Beckman instruments (6-month period, same QC lot, n > 100 points for each instrument) determined likely real-world consequences.

Results: Compared to individual QC targets, common targets had an asymmetrical effect on systematic error detection, with one instrument assay losing detection power more than the other gained. If individual in-control assay standard deviations (SDs) differed, then common targets led to one assay failing QC more frequently. Applied to two analysers (95 QC levels and 45 tests), common targets reduced one instrument's error detection by ≥ 0.4 sigma on 15/45 (33%) of tests. Such targets also meant 14/45 (31%) of assays on one in-control instrument would fail over twice as frequently as the other (median ratio 1.62, IQR 1.20-2.39) using a 2SD rule.

Conclusions: Compared to instrument-specific QC targets, common targets can reduce the probability of detecting changes in individual assay performance and cause one in-control assay to fail QC more frequently than another. Any impact on clinical care requires further investigation.

Background: Cell-free DNA (cfDNA) is free DNA found in circulating blood that originates from apoptosis or necrosis, and elevated cfDNA concentrations have been reported in cancers and other diseases.

Methods: In this study, the concentrations and fragment distributions of plasma cfDNA were preliminary investigated in elderly (n = 1) and paediatric (n = 1) patients with acute promyelocytic leukaemia (APL) treated with arsenic trioxide (ATO).

Results: A slight increase in cfDNA concentrations was observed in the APL patients compared with healthy controls. The change in plasma cfDNA concentrations corresponded to the change in plasma arsenic concentrations during ATO treatment. The fragment distribution pattern did not differ before and during treatment. Three ladder fragments were observed in part of the cfDNA in the second consolidation therapy in an elderly APL patient and the first consolidation therapy of a paediatric APL patient, while two fragments were observed in all other treatment periods. Moreover, APL-related gene mutations were successfully genotyped from plasma cfDNA by using polymerase chain reaction-based methods and these results are consistent with those from leukocytes.

Conclusion: This study is the first to report the concentrations and fragment patterns of cfDNA from APL patients treated with ATO. The results suggested that plasma cfDNA concentration in APL patients increased with ATO treatment and that cfDNA is released mainly via neutrophil extracellular traps (and/or necrosis) in addition to apoptosis. To confirm whether cfDNA concentrations and fragment patterns can be used as a biomarker for APL treated with ATO, further accumulative data are needed.

Background: Ketamine is an NMDAR antagonist with aggregating use across many areas of medicine. P450 enzymes heavily metabolise ketamine, where norketamine is a first pass formed metabolite following initial N-demethylation. Serum ketamine monitoring is becoming increasingly important, requiring a sensitive method with a robust lower limit of quantitation.

Methods: Samples were prepared using protein precipitation or solid phase extraction. Ion suppression was investigated to optimise sample preparation technique, followed by reverse-phase chromatography coupled with tandem mass spectrometry to analyse extractions using a Waters Xevo TQ-S Micro and associated Acquity chromatography systems. Performance characteristics were analysed to validate the assay.

Results: Ketamine and norketamine retention times were 1.28 and 1.23 min, respectively. Ketamine and norketamine precursor ions fragmented into 2 distinguishable product ions (238.14 > 207.18/125.06 and 224.1 > 178.96/124.86). Performance characteristics include an assay recovery of 103.7% (ketamine) and 96.3% (norketamine), lower limit of quantitation 36.2 µg/L (ketamine) and 38.9 µg/L (norketamine), and intra-assay imprecision ≤ 7.04% on average.

Conclusions: A robust and reproducible assay with limited sample preparation has been designed and validated. The linearity of the assay covers all ranges of interest reported in the literature. Ion suppression was clearly reduced via use of solid phase extraction. The method will form the basis of ketamine monitoring and providing valuable patient information on tolerance and metabolism.

Background: To accurately assess hypogammaglobulinemia at birth, it is essential to determine the reference intervals of serum immunoglobulin (IgG) levels in newborns. In the present study, we determined the gestational age (GA)-/birth weight (BW)-dependent percentile-based reference intervals of serum IgG levels and converted them into simple formulas for practical use.

Methods: Serum IgG levels were measured in cord blood from 2902 newborns delivered at 22 to 41 weeks of GA or 264 to 4642 g of BW after exclusion of those with congenital disorders. Linear regression analysis was used to correlate GA and UC-IgG levels and BW and UC-IgG levels. After calculation of the percentile values of UC-IgG levels for each GA or BW, the distributions were approximated by the least-squares method. Fitness was evaluated by the coefficient of determination (R²).

Results: Significant positive correlations were found both between GA and UC-IgG levels (r_s = 0.790, P < 0.001) and BW and UC-IgG levels (r_s = 0.626, P < 0.001). The distribution of the 5%ile of UC-IgG levels (Y) by GA or BW (X) was approximated as a straight line (Y = 37.5 *X - 775.8; Y = 0.161 *X + 95.34, respectively). The fitness was stronger in the GA-derived formula than the BW-derived formula (R² = 0.973 vs 0.913).

Conclusions: We established GA-/BW-dependent reference percentile-based intervals for serum IgG levels using cord blood from 2902 newborns without congenital disorders. Using GA-dependent reference intervals may be useful for assessing hypogammaglobulinemia at birth.

Background: Gestational hypothyroidism has been shown to be associated with adverse pregnancy outcomes as well as adverse outcomes for the child. Thyroid hormones concentrations change in gestation, especially within the first trimester, so the results of thyroid function test often are outside non-pregnant reference ranges. The objective of this study was to establish the first trimester reference ranges for thyroid stimulating hormone (TSH) and free thyroxine (FT4) for pregnant women in Barcelona (Spain).

Methods: It was a prospective study in which 673 women were recruited during their first trimester of gestation (8-13 weeks). Serum TSH, FT4 and antithyroid peroxidase antibodies (TPOAb) were measured with Atellica^® IM 1600 (Siemens Healthineers). After excluding 418 women, the reference ranges for TSH and FT4 were calculated by the 2.5th and 97.5th percentiles. Potential variables examined in this study were age, body mass index (BMI), ethnicity, iodine supplementation and smoking habit.

Results: The reference ranges established on the Atellica^® IM 1600 for the first trimester pregnancy in our population were 0.111 to 4.291 mIU/L for TSH and 11.45 to 17.76 pmol/L for FT4. No significant differences were found in thyroid hormones concentrations regarding maternal age (≤30 years vs >30 years) (p = .117), iodine supplementation (p = .683) and smoking habit (p = .363). The prevalence of TPOAb was estimated at 10.0%.

Conclusions: We found that in our local population, the optimal TSH upper reference limit in the first trimester of gestation was 4.3 mIU/L, similar to that proposed by de ATA-2017 guideline (4.0 mIU/L).

Background and objective: The disaccharide loading test is a method to assess gastric mucosal damage. Since Trelan-G75, which is used for the sugar tolerance test, contains disaccharide maltose, if maltose is detected at a high sensitivity in the sample blood used in the sugar tolerance test, screening for upper gastrointestinal mucosal damage can be made simultaneously with the sugar tolerance test for the diagnosis of diabetes.

Methods: Glucose-6-phosphate is generated by treating maltose with maltose phosphorylase, β-phosphoglucomutase, and glucose-1,6-bisphosphate. Then, change in the absorbance at 405 nm is measured by the enzymatic cycling method using Thio-NADP, β-NADPH, and Glucose-6-phosphate dehydrogenase. After evaluating the optimal condition for this method, it is mounted on an automatic biochemical analyzer, and samples after the sugar tolerance test were assayed.

Results: Regarding the performance of this method, the repeatability was 10-50 μmol/L with a CV of ≤1.1%. Concerning the assay range, a curve passing the origin with a range of linearity up to 120 μmol/L was obtained. No effect of dyes or sugars in the blood was noted. As a result of application to patients with gastric mucosal disorders (those who had a health checkup), significant differences were observed depending on the stage of atrophic gastritis.

Discussion: This method has a high sensitivity and a high precision and can be used for high-speed analysis on an automatic analyzer. It has the potential to be used as a screening test for gastric mucosal damage.