Background: Quality control (QC) validation is an important step in the laboratory harmonization process. This includes the application of statistical QC requirements, procedures, and control rules to identify and maintain ongoing stable analytical performance. This provides confidence in the production of patient results that are suitable for clinical interpretation across a network of veterinary laboratories.Objectives: To determine that a higher probability of error detection (P ed ) and lower probability of false rejection (P fr ) using a simple control rule and one level of quality control material (QCM) could be achieved using observed analytical performance than by using the manufacturer's acceptable ranges for QCM on the Sysmex XT-2000iV hematology analyzers for veterinary use. We also determined whether Westgard Sigma Rules could be sufficient to monitor and maintain a sufficiently high level of analytical performance to support harmonization.Methods: EZRules3 was used to investigate candidate QC rules and determine the P ed and P fr of manufacturer's acceptable limits and also analyzer-specific observed analytical performance for each of the six Sysmex analyzers within our laboratory system using the American Society of Veterinary Clinical Pathology (ASVCP)-recommended or internal expert opinion quality goals (expressed as total allowable error, TE a ) as the quality requirement. The internal expert quality goals were generated by consensus of the Quality, Education, Planning, and Implementation (QEPI) group comprised of five clinical pathologists and seven laboratory technicians and managers. Sigma metrics, which are a useful monitoring tool and can be used in conjunction with Westgard Sigma Rules, were also calculated. Results:The QC validation using the manufacturer's acceptable limits for analyzer 1 showed only 3/10 measurands reached acceptable P ed for veterinary laboratories (>0.85). For QC validation based on observed analyzer performance, the P ed was >0.94 using a 1-2.5s QC rule for the majority of observations (57/60) across the group of analyzers at the recommended TE a . We found little variation in P fr between manufacturer acceptable limits and individual analyzer observed performance as this is a characteristic of the rule used, not the analyzer performance.

Background Laboratory and instrument harmonization is seldom reported in the veterinary literature despite its advantages to clinical interpretation, including the use of interchangeable results and common reference intervals within a system of laboratories. Objectives A three‐step process was employed to evaluate and optimize performance and then assess the appropriateness of common reference intervals across a network of six Sysmex XT‐2000iV hematology analyzers at 5 commercial veterinary laboratory sites. The aims were to discover if harmonization was feasible in veterinary hematology and which quality parameters would best identify performance deviations to ensure a harmonized status could be maintained. Methods The performance of 10 measurands of a commercially available quality control material (Level 2—Normal e‐CHECK (XE)‐Hematology Control) was evaluated during three 1‐month time periods. Precision and bias were assessed with Six Sigma, American Society of Veterinary Clinical Pathology (ASVCP) total error quality goals and biologic variation (BV)‐based quality goal approaches to performance measurement. Results Instrument adjustments were made to 1 analyzer twice and 3 analyzers once between evaluations to improve performance and achieve harmonization. Sigma metrics improved from 37/50 > 6 to 58/60 > 6 and to all >5 over the course of the harmonization project. BV‐based quality goals for desirable bias and for laboratory systems of 0.33 × CVI (within‐subject biologic variation) were more sensitive and useful for assessing performance than the ASVCP total error goals. Conclusions Optimization and harmonization were achieved, and because BV‐derived bias goals were achieved, common reference intervals could be implemented across the network of analyzers.

BackgroundRepeat patient testing‐quality control (RPT‐QC) uses retained patient samples as an alternative to commercial quality control material (QCM). We elected to calculate and validate RPT‐QC limits for red blood cell count (RBC), hemoglobin (HBG), hematocrit (HCT), and white blood cell count (WBC).Objectives(1) To validate RPT‐QC across a network of four harmonized Sysmex XT‐2000iV hematology analyzers and determine the total error that can be controlled with RPT‐QC. (2) To generate quality control (QC) limits using the standard deviation (SD) of the duplicate measurement differences and determine a suitable simple QC rule with a probability of error detection >0.85 and probability of false rejection <0.05. (3) Monitor RPT‐QC using sigma metrics as a performance indicator and (4) to challenge RPT‐QC to ensure acceptable sensitivity.MethodsFresh adult canine EDTA samples with results within reference intervals were selected and run again on days 2, 3, and 4. QC limits were generated from the SD of the duplicate measurement differences. The QC limits were challenged using interventions designed to promote unstable system performance. The total error detectable by RPT‐QC was determined using EZRULES 3 software.ResultsIn all, 20‐40 data points were needed for RPT‐QC calculations and validated using 20 additional data points. The calculated limits differed among the network of analyzers. The total error that could be controlled was the same or better than that of the manufacturer's commercially available quality control material using the same analyzer for all measurands except hematocrit, which required a higher total error goal than that proposed by ASVCP guidelines to achieve an acceptable probability of error detection. The challenges designed to mimic unstable system performance were successfully detected as out‐of‐control QC.ConclusionsThe challenges for RPT‐QC resulted in acceptable detection of potential unstable system performance. This initial study demonstrates that RPT‐QC limits differ among the network of Sysmex XT‐2000iV analyzers, indicating a requirement to customize for the individual analyzer and laboratory conditions. RPT‐QC could achieve ASVCP total allowable error goals for RBC, HGB, and WBC, but not for HCT. Sigma metrics were consistently >5.5 for RBC, HGB, and WBC, but not for HCT.