Searching for the urine osmolality surrogate: an automated machine learning approach

OBJECTIVES

Automated machine learning (AutoML) tools can help clinical laboratory professionals to develop machine learning models. The objective of this study was to develop a novel formula for the estimation of urine osmolality using an AutoML tool and to determine the efficiency of AutoML tools in a clinical laboratory setting.

METHODS

Three hundred routine urinalysis samples were used for reference osmolality and urine clinical chemistry analysis. The H2O AutoML engine completed the machine learning development steps with minimum human intervention. Four feature groups were created, which include different urinalysis measurements according to the Boruta feature selection algorithm. Method comparison statistics including Spearman correlation, Passing-Bablok regression analysis were performed, and Bland Altman plots were created to compare model predictions with the reference method. The minimum allowable bias (24.17%) from biological variation data was used as the limit of agreement.

RESULTS

The AutoML engine developed a total of 183 ML models. Conductivity and specific gravity had the highest variable importance. Models that include conductivity, specific gravity, and other urinalysis parameters had the highest R² (0.70-0.83), and 70-84% of results were within the limit of agreement.

CONCLUSIONS

Combining urinary conductivity with other urinalysis parameters using validated machine learning models can yield a promising surrogate. Additionally, AutoML tools facilitate the machine learning development cycle and should be considered for developing ML models in clinical laboratories.

Isoquercitrin protects HUVECs against high glucose‑induced apoptosis through regulating p53 proteasomal degradation

High glucose (HG)-induced endothelial apoptosis serves an important role in the vascular dysfunction associated with diabetes mellitus (DM). It has been reported that isoquercitrin (IQC), a flavonoid glucoside, possesses an anti-DM effect, but the mechanism requires further investigation. The present study investigated the effect of IQC against HG-induced apoptosis in human umbilical vein endothelial cells (HUVECs) and explored its molecular mechanism. HUVECs were treated with 5 or 30 mM glucose for 48 h. Endothelial cell viability was monitored using the Cell Counting Kit-8 assay. Mitochondrial membrane potential was detected by JC-1 staining. Apoptosis was observed by TUNEL staining and flow cytometry. Western blotting was used for the analysis of apoptosis-associated proteins Bax, Bcl-2, cleaved (C)-caspase3, total-caspase3, p53 and phosphorylated p53. Reverse transcription-quantitative PCR was used to analyze the mRNA expression levels of Bax, Bcl-2 and p53. Immunofluorescence staining was utilized to detect the expression levels and distribution of p53 and ubiquitin specific peptidase 10 (USP10) in HUVECs. The results revealed that IQC significantly attenuated HG-induced endothelial apoptosis, as shown by decreased apoptotic cells observed by TUNEL, JC-1 staining and flow cytometry. Moreover, under HG stress, IQC treatment markedly inhibited the increased expression levels of the pro-apoptotic proteins p53, Bax and C-caspase3, and increased the expression levels of the anti-apoptotic protein Bcl-2 in HUVECs. However, the anti-apoptotic effect of IQC against HG was partially blunted by increasing p53 protein levels in vitro. IQC influenced the mRNA expression levels of Bax and Bcl-2 in response to HG, but it did not affect the transcription of p53. Notably, IQC inhibited the HG-induced phosphorylation of p53 at Ser15 and the nuclear transport of USP10, destabilizing p53 and increasing the proteasomal degradation of the p53 protein. The current findings revealed that IQC exerted a protective effect against the HG-induced apoptosis of endothelial cells by regulating the proteasomal degradation of the p53 protein, suggesting that IQC may be used as a novel therapeutic compound to ameliorate DM-induced vascular complications.

Analysis of performance of clinical biochemistry laboratory using Sigma metrics and Quality Goal Index

Background

Unreliable and ingenuine results issued by clinical laboratories have serious consequences for the patients. Sigma metrics is a standardized tool for Quality assessment for test performance in a laboratory.

Objective

To evaluate the performance of routine biochemistry laboratory at MMIMSR, Mullana in terms of Sigma metrics and Quality Goal Index.

Material and methods

This cross sectional study evaluated performance of 14 routine chemistry parameters using retrospective Internal Quality Control data of two levels on Siemens Dimension Rxl from Feb to Jul 2019 for CV% and EQAS reports from CMC, Vellore for Bias%. Sigma metrics was calculated using total allowable error targets as per CLIA and Biological Variability database guidelines.

Results

For level-2 IQC; TG, Chol, ALP showed excellent performance with σ ​> ​6 while σ ​< ​3 was observed for AST, Total Protein, Glucose, BUN and ALT using CLIA guidelines while in IQC Level-3 poor performers were only BUN and ALT with Ca, TG and Chol showing σ ​> ​6. Further by using Biological Variability data guidelines; 10 parameters of IQC Level-2 and 5 of IQC level-3 were poor performers with σ ​< ​3.

Conclusion

Sigma metrics is an excellent tool for performance analysis of tests performed in a clinical laboratory. Lack of precision in terms of CV% was seen for majority of the poor performers. Total allowable error targets using Biological Variability data revealed σ ​< ​3 for 10 parameters while using CLIA guidelines σ ​< ​3 was seen for only 5 parameters of IQC level-2.

Quality Control of Norwegian Pharmacy HbA1c Testing: A Modest Beginning

BACKGROUND

Many pharmacy services involve laboratory testing using point-of-care (POC) instruments. Our aim was to describe the implementation of quality control of the HbA1c POC instruments and investigate the performance in internal quality control (IQC) and external quality control (EQA) for HbA1c POC instruments in Norwegian community pharmacies.

METHODS

Two project pharmacists from each of 11 pharmacies participated in a training program covering capillary blood sampling, how to use the POC HbA1c instrument (DCA Vantage) and IQC and EQA. The pharmacies were enrolled in an EQA program for HbA1c, and their performance was compared with that of general practitioners' (GP) offices.

RESULTS

Two of 89 (2.2%) IQC measurements were outside the acceptance interval. Seven out of 11 pharmacies sent in results in EQA in all the three surveys during six months. Two pharmacies did not analyze the control material in any of the surveys, one pharmacy analyzed the control material in one of the surveys, and one pharmacy analyzed two of the surveys. Of these pharmacies, 56-100% obtained "very good" evaluation for trueness and 71-100% obtained "very good" evaluation for precision. The corresponding numbers for GP offices were 75-87% for trueness and 84-94% for precision. No pharmacies obtained a "poor" evaluation.

CONCLUSIONS

Norwegian community pharmacies can perform IQC and EQA on a HbA1c POC instrument, and the performance is comparable with that of GP offices. The compliance in the EQA surveys was modest, but the duration of the study and participation in the EQA program was probably too short to implement all the new procedures for all pharmacies.

An update on quality control for the PFA-100/PFA-200

Testing of platelet function comprises a crucial element of hemostasis assessment, particularly for investigations into bleeding and/or bruising. The Platelet Function Analyzer (PFA)-100 is the most utilized primary hemostasis-screening test system available, as recently remodeled/upgraded to the PFA-200. Internal quality control (IQC) and external quality assessment (EQA) (including proficiency testing) represent critical elements of ensuring test practice quality. Although true for all tests, IQC and EQA are logistically challenging for platelet function testing, inclusive of the PFA-100/200. We accordingly update our experience with novel yet feasible approaches to both IQC and EQA of PFA-100/200. Over the past 10 years, a total of 43 challenges have been tested, with most challenges designed to mimic moderate or severe primary hemostasis defects. The current report is restricted to the last four years and has also differentially assessed PFA-100 vs. PFA-200 EQA results to identify potential variance. Numerical results for closure times (CTs) and participant-supplied interpretive comments were analyzed. Reported CTs for each challenge were within limits of expectation, and good reproducibility was evidenced by repeated challenges. Coefficients of variation (CVs) for challenges, generally ranging from 15% to 25%, were similar or better than those obtained using native whole blood and consistent with past reports. Participant interpretations were generally consistent with test data and expectations. There was no evident difference in PFA-100 vs. PFA-200 EQA test results. The EQA material has also been successfully evaluated from the perspective of potential IQC. To conclude, IQC and EQA processes for the PFA-100/200 have been established that are highly reproducible, supporting the concept of EQA/IQC for platelet function testing, and also facilitating monitoring and improvement in its performance. In terms of EQA, PFA-100 and PFA-200 instruments appear to behave similarly.

Duplicate analysis method: a cheaper alternative to commercial IQC materials in limited resource settings for monitoring CD4 testing

BACKGROUND

India has a large number of HIV infected patients being followed up at anti-retroviral therapy (ART) centers. The patients are regularly offered CD4 count estimation for deciding their eligibility for ART initiation as well as for monitoring response to ART, making CD4 count estimation a very critical test. Hence, quality control of CD4 testing is utmost important for ultimate success of ART program. As the commercial controls are very expensive, internal quality control (IQC), at present, is being done by duplicate analysis method using previous day samples in most of the laboratories. Hence the study was undertaken to review performance of duplicate analysis method for monitoring daily IQC.

METHODS

Quality control (QC) data from 11 Indian laboratories using duplicate analysis and/or commercial controls for IQC of CD4 testing was collected for reviewing information on QC parameters such as precision, accuracy and trend monitoring. Precision was determined by r(2) values and mean % variation for duplicate analysis and coefficient of variation (% CV) for commercial controls. Accuracy was monitored by rate of QC failures for both the types of control and trend monitoring was done by plotting LJ charts for commercial controls and by plotting daily % variation for duplicate analysis.

RESULTS

The laboratories using duplicate analysis for IQC showed good precision with mean % variation ranging from 0.5 to 7.2. There was good match between r(2) values and % CV of the laboratories performing both the types of QC methods. Rates of QC failures were 2.3 for duplicate analysis and 3 per laboratory-year for IMMUNO-TROL controls. Daily trend monitoring showed fluctuation of daily counts around mean in LJ charts and of percent variation around 0% in duplicate analysis method. Commercially available controls showed limitations such as altered specimen quality leading to difficulties in manual gating and issues with the establishment of laboratory range.

CONCLUSION

Duplicate analysis can serve as a cheaper alternative to commercially available controls for IQC of CD4 testing especially when supplemented with other QC measures for controlling variations caused by reagent, equipment, staff and environment in addition to the successful participation in External Quality Assurance programme.

Stability of lyophilized human serum for use as quality control material in bhutan

Quality control (QC) materials are crucial for internal quality control (IQC) and external quality assessment scheme (EQAS). However, many developing countries are disadvantaged by unavailability and high cost of commercial control material. Therefore, preparing home-made lyophilized human serum will be cost effective for used as a QC material in Bhutan. We prepared lyophilized QC material using serum collected from Bhutanese volunteers. The stability of lyophilized serum was studied at 3 selected conditions by analyzing at certain intervals. The results were statistically compared with initial values. The significant p values (<0.05) were seen in glucose, BUN, ALT, total bilirubin and protein at 2-8 °C but no significant difference were observed at -20 °C at the end of 9 months. We concluded that, home-made lyophilized human serum prepared without stabilizers could be used at least up to 9 months if stored at -20 °C and 7 months at 2-8 °C. Stabilizers and additives are necessary if the materials are to be used longer than 7-9 months.

Comparison of markers of coagulation activation and thrombin generation test in uncomplicated pregnancies

INTRODUCTION

Pregnancy is a well-established risk factor for venous thromboembolism, and is associated with a state of hypercoagulability or parameters of thrombin generation. Currently, there is a lack of consensual data on thrombin generation during pregnancy. This study aimed to find a sensitive and specific biological marker of coagulation activation and to identify parameters of thrombin generation.

PATIENTS AND METHODS

The population included 101 women with uncomplicated pregnancies. The objective of this study was to correlate thrombin generation test (measured at 5pM tissue factor, 4μM lipids and without thrombomodulin), with fibrinogen and markers of blood coagulation activation: D-dimer, prothrombin fragments 1+2 (F1+2), thrombin-antithrombin complexes (TAT) and fibrin monomer complexes (FMC) in these women. Internal quality control was performed in each set of experiments.

RESULTS

Fibrinogen, D-dimer, F1+2, and TAT concentrations increased significantly throughout pregnancy, and were correlated with term of pregnancy. In our study, thrombin generation seemed to increase early on, and then remained stable throughout normal pregnancy, in contrast with other markers of blood coagulation activation, excepting FMC. The latter are subject to large inter-individual variations, especially during second trimester. No correlation was demonstrated between thrombin generation parameters and other activation markers.

CONCLUSION

While markers of coagulation activation significantly increased during pregnancy, thrombin generation increased only early on and remains stable during pregnancy. Finding a sensitive and specific biological marker for vascular pregnancy complications, such as FMC and thrombin generation levels, requires further investigation.

Trace elements and endometriosis: the ENDO study

There has been limited study of trace elements and endometriosis. Using a matched cohort design, 473 women aged 18-44 years were recruited into an operative cohort, along with 131 similarly aged women recruited into a population cohort. Endometriosis was defined as surgically visualized disease in the operative cohort, and magnetic resonance imaging diagnosed disease in the population cohort. Twenty trace elements in urine and three in blood were quantified using inductively coupled plasma mass spectrometry. Logistic regression estimated the adjusted odds (aOR) of endometriosis diagnosis for each element by cohort. No association was observed between any element and endometriosis in the population cohort. In the operative cohort, blood cadmium was associated with a reduced odds of diagnosis (aOR=0.55; 95% CI: 0.31, 0.98), while urinary chromium and copper reflected an increased odds (aOR=1.97; 95% CI: 1.21, 3.19; aOR=2.66; 95% CI: 1.26, 5.64, respectively). The varied associations underscore the need for continued research.