A step towards optimal efficiency of HbA1c measurement as a first-line laboratory test: the TOP-HOLE (Towards OPtimal glycoHemOgLobin tEsting) project.

OBJECTIVES: The TOP-HOLE (Towards OPtimal glycoHemOgLobin tEsting) project aimed to validate the HbA1c enzymatic method on the Abbott Alinity c platform and to implement the HbA1c testing process on the total laboratory automation (TLA) system of our institution. METHODS: Three different measuring systems were employed: Architect c4000 stand-alone (s-a), Alinity c s-a, and Alinity c TLA. Eight frozen whole blood samples, IFCC value-assigned, were used for checking trueness. A comparison study testing transferability of HbA1c results from Architect to Alinity was also performed. The alignment of Alinity TLA vs. s-a was verified and the measurement uncertainty (MU) estimated according to ISO 20914:2019. Turnaround time (TAT) and full time equivalent (FTE) were used as efficiency indicators. RESULTS: For HbA1c concentrations covering cut-offs adopted in clinical setting, the bias for both Architect and Alinity s-a was negligible. When compared with Architect, Alinity showed a mean positive bias of 0.54 mmol/mol, corresponding to a mean difference of 0.87%. A perfect alignment of Alinity TLA to the Alinity s-a was shown, and a MU of 1.58% was obtained, widely fulfilling the desirable 3.0% goal. After the full automation of HbA1c testing, 90% of results were released with a maximum TAT of 1 h, 0.30 FTE resource was also saved. CONCLUSIONS: The traceability of Alinity HbA1c enzymatic assay to the IFCC reference system was correctly implemented. We successfully completed the integration of the HbA1c testing on our TLA system, without worsening the optimal analytical performance. The shift of HbA1c testing from s-a mode to TLA significantly decreased TAT.

Cystatin C provides a better estimate of the effect of glomerular filtration rate on serum human epididymis protein 4 concentrations.

BACKGROUND: We evaluated the effect of kidney glomerular function on serum concentrations of human epididymis protein 4 (HE4) using creatinine (Cr), cystatin C (CysC) and related chronic kidney disease epidemiology collaboration (CKD-EPI) equations. METHODS: We enrolled 101 women aged ≤56 years with a glomerular filtration rate (GFR) (estimated by CKD-EPI eGFRCr) ranging from 60 to 120 mL/min/1.73 m2, free of any disease and biological and life-style factors known to influence serum HE4 concentrations, and we measured serum Cr, CysC and HE4 concentrations. Cr and CysC values were included in the three CKD-EPI equations to obtain GFR estimates. RESULTS: A statistically significant increase in HE4 median concentrations was detected in subjects with an eGFRCr between 60 and 74 mL/min/1.73 m2 when compared with those with an eGFR >90 mL/min/1.73 m2 (54.2 vs. 42.2 pmol/L, p=0.003). Regression models showed that CysC measurement per se and eGFRCysC were the most sensitive markers to catch HE4 increases due to a mild decrease in renal function [adjusted r2, 0.38 (p=0.00003) and 0.37 (p=0.0004), respectively]. By assuming baseline CysC and eGFRCysC at 0.80 mg/L and 101.5 mL/min/1.73 m2, an increase of 0.10 mg/L in CysC concentrations and a decrease of 10 mL/min of eGFRCysC implied an average (±SE) increase in serum HE4 concentrations of 9.2 (±1.2) and 8.8 (±1.1) pmol/L, respectively. CONCLUSIONS: Our study shows that a better estimate of the effect of GFR on serum HE4 is obtained by measuring CysC in serum or using CKD-EPI eGFRCysC equation.

Verification of the harmonization of human epididymis protein 4 assays.

BACKGROUND: Serum human epididymis protein 4 (HE4) has gained relevance as an ovarian cancer (OC) biomarker and new automated methods have replaced the first released manual EIA by tracing results to it. We verified agreement and bias of automated methods vs. EIA as well as possible effects on patients' management. METHODS: One hundred and fifteen serum samples were measured by Abbott Architect i2000, Fujirebio Lumipulse G1200, Roche Modular E170, and Fujirebio EIA. Passing-Bablok regression was used to compare automated assays to EIA and agreement between methods was estimated by Lin's concordance correlation coefficient (CCC). The bias vs. EIA was estimated and compared to specifications derived from HE4 biological variation. RESULTS: Median (25th-75th percentiles) HE4 concentrations (pmol/L) were 84.5 (60.1-148.8) for EIA, 82.7 (50.3-153.9) for Abbott, 89.1 (55.2-154.9) for Roche, and 112.2 (67.8-194.2) for Fujirebio. Estimated regressions and agreements (95% confidence interval) were: Abbott=1.01(0.98-1.03) EIA-4.8(-7.5/-2.6), CCC=0.99(0.99-1.00); Roche=0.91(0.89-0.93) EIA+5.7(4.2/8.0), CCC=0.98(0.98-0.99); Fujirebio=1.20(1.17-1.24) EIA+ 2.4(-0.6/4.9), CCC=0.97(0.96-0.98). The average bias vs. EIA resulted within the desirable goal for Abbott [-3.3% (-6.1/-0.5)] and Roche [-0.2% (-3.0/2.5)]. However, while for Abbott the bias was constant and acceptable along the measurement concentration range, Roche bias increased up to -28% for HE4 values >250 pmol/L. Lumipulse showed a markedly positive bias [25.3% (21.8/28.8)]. CONCLUSIONS: Abbott and Roche assays exhibited a good comparability in the range of HE4 values around the previously recommended 140 pmol/L cut-off. For patient monitoring, however, the assay used for determining serial HE4 must not be changed as results from different systems in lower and higher concentration ranges can markedly differ.

Random uncertainty of photometric determination of hemolysis index on the Abbott Architect c16000 platform.

BACKGROUND: Automatic photometric determination of the hemolysis index (HI) on serum and plasma samples is central to detect potential interferences of in vitro hemolysis on laboratory tests. When HI is above an established cut-off for interference, results may suffer from a significant bias and undermine clinical reliability of the test. Despite its undeniable importance for patient safety, the analytical performance of HI estimation is not usually checked in laboratories. Here we evaluated for the first time the random source of measurement uncertainty of HI determination on the two Abbott Architect c16000 platforms in use in our laboratory. METHODS: From January 2016 to September 2017, we collected data from daily photometric determination of HI on a fresh-frozen serum pool with a predetermined HI value of ~100 (corresponding to ~1g/L of free hemoglobin). Monthly and cumulative CVs were calculated. RESULTS: During 21months, 442 and 451 measurements were performed on the two platforms, respectively. Monthly CVs ranged from 0.7% to 2.7% on c16000-1 and from 0.8% to 2.5% on c16000-2, with a between-platform cumulative CV of 1.82% (corresponding to an expanded uncertainty of 3.64%). Mean HI values on the two platforms were just slightly biased (101.3 vs. 103.1, 1.76%), but, due to the high precision of measurements, this difference assumed statistical significance (p<0.0001). CONCLUSIONS: Even though no quality specifications are available to date, our study shows that the HI measurement on Architect c16000 platform has nice reproducibility that could be considered in establishing the state of the art of the measurement.