Annals of Clinical Biochemistry: International Journal of Laboratory Medicine

Measurement of testosterone (T), androstenedione (A4) and 17-hydroxyprogesterone (17OHP) usually requires a venous serum sample which may have implications for sample stability or collection.

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay was developed for samples collected using Mitra devices. Analytical validation was completed, and sample comparisons were undertaken to assess Mitra versus venous samples.

Sample was combined with deionized water and internal standard. After mixing, MTBE was added for extraction. The supernatant was transferred to a deep-well plate and dried prior to re-constitution. A HSS T3 column and Waters TQS Micro was used, the detected quantifier transitions were T m/z 289.2 > 96.95, A4 287.2 > 96.95 and 17OHP 331.25 > 96.95.

Mean recovery was 102% for T, 98% for A4 and 97% for 17OHP. Lower limit of quantification was 1 nmol/L for T/A4 and 4 nmol/L for 17OHP. T was linear up to 41.6 nmol/L, A4 41.9 nmol/L and 17OHP 72.6 nmol/L. Ion suppression was <10% for all analytes. A4 and 17OHP showed minimal bias for Mitra samples collected from finger prick blood. The bias for T differed between capillary and venous blood, indicating differences in constituency.

A simple, fast and reproducible LC-MS/MS assay has been developed for measurement of blood collected using Mitra devices for T, A4 and 17OHP. Further comparisons with serum and capillary blood collected onto Mitra devices serum may pave the way for future use in a clinical setting.

Myonectin, a newly discovered myokine, enhances fatty acid uptake in cultured adipocytes and hepatocytes and suppresses circulating levels of free fatty acids in mice. Recent studies showed that serum myonectin concentration is negatively correlated with obesity. This study was undertaken to evaluate the change of serum myonectin in obese patients after laparoscopic sleeve gastrectomy.

This study was performed in a population of 42 obese and 58 control subjects from April of 2018 to December of 2019. All obese subjects underwent laparoscopic sleeve gastrectomy. Anthropometric measurements, lipid profiles, HbA1c and serum myonectin were assessed at baseline and six months after laparoscopic sleeve gastrectomy.

Serum myonectin concentrations were significantly lower in the obese patients than in the controls. Serum myonectin concentrations were increased at six months after laparoscopic sleeve gastrectomy. Simple linear regression analysis indicated that serum myonectin was negatively correlated with weight, waist circumference, hip circumference, body mass index, fasting plasma glucose, homeostasis model assessment of insulin resistance and HbA1c. Only body mass index was still inversely correlated with serum myonectin after multiple linear regression analysis.

Serum myonectin is correlated with obesity and increased after laparoscopic sleeve gastrectomy.

Our study aims to explore the effect of serum long non-coding RNA (lncRNA) H19 level on the long-term prognosis of endoscopic keyhole surgery or craniotomy for glioma.

A total of 264 glioma patients were selected. Patients were randomly divided into the Craniotomy-high H19 group, the Craniotomy-low H19 group, the Endoscopic keyhole surgery-high H19 group and the Endoscopic keyhole surgery-low H19 group.

Compared with adjacent tissues (5.19 ± 1.42), H19 level in cancer tissues (7.45 ± 1.60) and serum (6.44 ± 1.57) was significantly increased (P < 0.05). Compared with serum, H19 level in cancer tissues was significantly increased (P < 0.05). Pearson correlation analysis found that the relative expression level of serum H19 in glioma patients was positively correlated with cancer tissues (r_Pearson = 0.547, P < 0.001), but had no significant correlation with adjacent tissues (r_Pearson = 0.126, P  =  0.207). The expression of H19 in serum was significantly related to WHO grade (r_Pearson = 0.514, P < 0.001). Compared with the Endoscopic keyhole surgery-high H19 group and the Endoscopic keyhole surgery-low H19 group, the survival rate of patients in the Craniotomy-high H19 group (χ² = 17.115 and log-rank P < 0.001; χ² = 18.406 and log-rank P < 0.001) and the Craniotomy-low H19 group was significantly reduced (χ² = 15.007 and log-rank P < 0.001; χ² = 16.121 and log-rank P < 0.001). Cox regression results showed that serum H19 level, craniotomy and WHO grade were risk factors for glioma. When H19 level was lower than 6.28, the 30-month survival rate of patients with the endoscopic keyhole surgery was 100%.

For patients with low H19 level (<5.36), both endoscopic keyhole surgery and craniotomy are available, otherwise, endoscopic keyhole surgery is more recommended.

Harmonization of reference intervals for analytes that have a sound calibration and metrological traceability is a widely recommended practice. The UK Pathology Harmony has recently harmonized reference intervals for calcium and albumin. In this study, we have determined the reference intervals for calcium and albumin on the UK’s most commonly used analytical platforms.

A prospective reference population of healthy individuals was recruited according to the IFCC CRIDL criteria. A second indirect population was collected from 14 primary care setting and measured in laboratories using various analytical platforms and methods (Roche, Abbott, Beckman and Siemens analytical platforms).

In total, 299 subjects were recruited; the central 95th centile values for calcium for three out of four analytical platforms were in a close agreement with UK Pathology Harmony reference intervals of 2.2–2.6 mmol/L. Reference intervals of BCG methods from both cohorts and irrespective of analytical platforms were higher for both lower and upper reference limits than those for BCP. In comparison, the indirect study showed an age-related variation. The younger population reference intervals varied by up to 5.7% at the lower reference limit and up to 12% at the upper reference limit compared with Pathology Harmony reference intervals, and the older population showed a variation of up to 14% at both limits.

While calcium reference intervals can be a subject for harmonization, albumin reference intervals studied showed large variation which is unsupportive of embracing a common reference interval for albumin.

The generation of accurate, comparable results from traceable measurement procedures is a primary goal in harmonization efforts. In this study, the analytical performance of routine methods for calcium and albumin measurement is assessed to define the impact of the analytical bias of calcium and albumin on adjusted calcium equation performance and on reference intervals.

In collaboration with the Wales External Quality Assurance Scheme, six months’ worth of anonymized data that cover a concentration range of clinical interest were collected. The data were grouped by analytical platforms/methods.

Albumin BCG methods are positively biased (8%) to BCP methods. The overall bias for BCP methods ranges from 5.1 to –4.3% and the overall bias for BCG methods is from 2 to –6.7%. Bias for both methods is higher than the allowable minimal bias for albumin. Calcium concentrations for Roche Cobas CPC and NM-BAPTA, Beckman Arsenazo III, Abbott Architect Arsenazo III were within bias of 1.5 to –1%. However, Siemens calcium methods CPC and Arsenazo III appear to suffer from concentration-dependent bias ranging from +3 to –6%, which exceeds even the minimal allowable limits for calcium (1.3%). Adjusted calcium shows significant bias of 11%. Even with the exclusion of Siemens Advia, the scatter of adjusted calcium results exceeds that for total calcium.

This study shows wider than acceptable analytical variation for albumin and calcium. This variation may contribute to overall adjusted calcium equations variation and invalidate the application of a harmonized reference interval for calcium and albumin.

Current practice requires regular venous blood samples for monitoring of tacrolimus concentrations post renal transplant requiring regular hospital visits. Mitra devices use volumetric absorptive microsampling technology and absorb a fixed amount of blood (10 μL) from a capillary blood sample. They are a viable volumetric alternative to dried blood spots and are able to be posted to the laboratory for analysis.

The aim was to develop and validate liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays for tacrolimus and creatinine analysis using Mitra devices. The usefulness of this approach was assessed in renal transplant patients routinely monitored for tacrolimus and creatinine.

Routine tacrolimus samples were used to assess the utility and reliability of Mitra sampling. Shared sample preparation for both tacrolimus and creatinine was carried out in a 96-deep well plate; mass spectrometric analysis was then undertaken for tacrolimus followed by re-injection for creatinine analysis.

Comparison of 131 Mitra samples with a routine LC-MS/MS assay for tacrolimus showed a minimal bias –5.6% (95% CI –8.5 to –2.7%). Comparison of 135 serum and Mitra samples for creatinine using a fully validated LC-MS/MS assay showed a bias –6.5% (95% CI –8.5 to –4.5%).

We have developed assays for tacrolimus and creatinine on fingerprick blood using the Mitra device and believe this approach provides a viable alternative to repeated venepuncture for therapeutic drug monitoring. This method could open up the opportunity for patients to perform tacrolimus and kidney function monitoring at home.