Quality control validation for a veterinary laboratory network of six Sysmex XT‐2000iV hematology analyzers

Abstract

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.

Repeat patient testing‐quality control with canine samples shows promise as an alternative to commercial quality control material for a network of four Sysmex XT‐2000iV hematology analyzers

“…The ASVCP recommended TE a goals could not be achieved for HCT on any of the analyzers with RPT-QC. This was not an unexpected finding as HCT is affected by MCV which has been previously found to increase with sample aging 10,11,14 and, therefore, was not included in this study. The inclusion of HCT was important despite the increased TE associated with differences used for RPT-QC.…”

“…A single level of commercial QCM (level 2 -Normal e-CHECK (XE)-Hematology Control), which is composed of stabilized human RBCs, human WBCs, platelets, and nucleated RBC components in a preservative medium, was analyzed once per day at analyzer startup, prior to analysis of patient samples, by a fully trained technician according to a standard operating procedure and was within accepted limits before assessing patient samples. 14 These measurands were chosen as those most useful in our network of laboratories for statistical QC. 14 Differential cell counts and platelet counts were considered to be more adequately assessed by nonstatistical QC by technician evaluations of blood smears.…”

“…14 These measurands were chosen as those most useful in our network of laboratories for statistical QC. 14 Differential cell counts and platelet counts were considered to be more adequately assessed by nonstatistical QC by technician evaluations of blood smears. 14…”

“…14 Differential cell counts and platelet counts were considered to be more adequately assessed by nonstatistical QC by technician evaluations of blood smears. 14…”

Repeat patient testing quality control (RPT‐QC): Background and theory

“…Prior studies suggest that 24 to 72 hours of storage at 4 to 5°C are suitable for RPT-QC using canine whole blood (hematology testing), and 7 days of storage is suitable for RPT-QC using plasma (chemistry testing). [9][10][11] Laboratory operations (eg, hours of operation, available personnel) may additionally impact time intervals chosen. In general, longer storage intervals (days) are likely to be most appropriate for stable specimens and analytes, whereas shorter time intervals (hours) are likely to be most appropriate for labile specimens and measurands (Figures 1 and 2).…”