Review of biological variation and its applications in interpretation of equine clinical pathology results.

Biological variation in laboratory results refers to physiological fluctuations that occur around a homeostatic setpoint (HSP) for various laboratory measurands. Assessment of biological variation includes determining individual variation (CV), group variation (CV), and analytical variation (CV). Reference change value (RCV) is an objective tool for an evidence-based approach to interpret data by assessing the significance of consecutive results in an individual for the diagnosis, prognosis, and monitoring of disease.

Impact of regression modeling on the assessment and harmonization of a point-of-care analyzer and commercial laboratory analyzer for feline plasma biochemistry testing.

Background: Regression describes the relationship of results from two analyzers, and the generated equation can be used to harmonize results. Point-of-care (POC) analyzers cannot be calibrated by the end user, so regression offers an opportunity for calculated harmonization. Harmonization (uniformity) of laboratory results facilitates the use of common reference intervals and medical decision thresholds.

Analytical performance of feline plasma on current Heska and IDEXX point-of-care biochemistry analyzers compared with a commercial laboratory analyzer.

Background: Point-of-care (POC) biochemistry analyzers are widely used in small animal clinical practice but infrequently independently assessed for performance.

Objective: To assess the performance of two current model point-of-care biochemistry analyzers (Heska Element DC and IDEXX Catalyst) compared with a commercial laboratory analyzer (Cobas 8000).

Methods: One hundred twenty-one cats from a feline hospital population were sampled with plasma results from a single lithium heparin tube assessed on all three analyzers.

The importance of quality control validation and relationships with total error quality goals and bias in the interpretation of laboratory results.

The objective of a quality system is to provide accurate and reliable results for clinical decision-making. One part of this is Quality Control (QC) validation. QC validation is not routinely applied in veterinary laboratories.

Veterinary clinicians prefer template-style reports with personal confidence estimates for cytologic sample evaluations.

Objective: To examine preferences of veterinary clinical pathologists, clinicians, and students for cytology report formats.

Sample: 24 clinical pathologists, 1,014 veterinarians, and 93 veterinary students who were members of the Veterinary Information Network.

Methods: Members of the Veterinary Information Network responded to an online survey invitation, made available between July 11, 2023, and July 24, 2023.

Repeat patient Testing-Quality control: An example of implementation in a network of commercial laboratories.

The theory and calculations underpinning Repeat Patient Testing-Quality Control (RPT-QC) have been presented in prior publications. This paper gives an example of the process used for implementing RPT-QC in a network of veterinary commercial reference laboratories and the stages associated with the transition to the sole use of RPT-QC. To employ RPT-QC in this commercial laboratory network, eight stages of implementation were identified: (1) education, (2) data collection, (3) calculations, (4) QC recording and documentation, (5) running RPT-QC in parallel with a commercially available quality control material (QCM), (6) development of a Standard Operating Procedure (SOP), (7) development of complementary aspects supporting RPT-QC, and (8) sole use of RPT-QC.

Preferences of clinical pathologists for probability-modifying terms describing cytologic sample evaluations: A survey study.

Background: A recent study identified 7 probability ranges used by clinical pathologists and associated qualitative terms used in cytology reports. Clinicians and clinical pathologists agreed that limiting the number of terms could help enhance communication between clinical pathologists and clinicians. However, the preferred terms for each range remain undetermined.

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

Repeat-patient testing quality control (RPT-QC) is a version of statistical quality control (SQC) in which individual patient samples, rather than commercial control materials, are used. Whereas conventional SQC assumes control material stability and repeatedly measures the same lot of control material over time, RPT-QC uses a unique patient sample for each QC event and exploits the labile nature of patient samples under prescribed storage conditions for QC purposes. Advantages of RPT-QC include commutability, lower cost, and QC at concentrations of medical interest.

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.

Background: Repeat 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.

Clinical pathologists should limit modifier terms used to denote probability of a diagnosis: a survey-based study.

Objective: To examine the probability estimates for modifying terms used by clinical pathologists when interpreting cytologic samples and compare these to probability estimates assigned to these terms by clinicians, and to provide restricted, standardizing terms used in cytology reports.

Sample: 49 clinical pathologists and 466 Veterinary Information Network members responded to 2 similar surveys.

Procedures: Online surveys were distributed to diplomates of the European College of Veterinary Clinical Pathologists and clinician members of the Veterinary Information Network, made available between March 17, 2022, through May 5, 2022.

Guidelines for resident training in veterinary clinical pathology. IV: Laboratory quality management-Teaching domains, competencies, and suggested learning outcomes.

Background: The 2019 ASVCP Education Committee Forum for Discussion, presented at the annual ASVCP/ACVP meeting, identified a need to develop recommendations for teaching laboratory quality management principles in veterinary clinical pathology residency training programs.

Objectives: To present a competency-based framework for teaching laboratory quality management principles in veterinary clinical pathology residency training programs, including entrustable professional activities (EPAs), domains of competence, individual competencies, and learning outcomes.

Methods: A joint subcommittee of the ASVCP Quality Assurance and Laboratory Standards (QALS) and Education Committees executed this project.

Recommendations to improve the patient experience and avoid bias when prenatal screening/testing.

While prenatal screening and testing have expanded substantially over the past decade and provide access to more genetic information, expectant parents are more likely to describe the diagnosis experience as negative than positive. In addition, the conversations that take place during these experiences sometimes reflect unconscious bias against people with disabilities. Consequently, an interdisciplinary committee of experts, including people with disabilities, family members, disability organization leaders, healthcare and genetics professionals, and bioethicists, reviewed selected published and gray literature comparing the current state of the administration of prenatal testing to the ideal state.

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

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.

Total observed error, total allowable error, and QC rules for canine serum and urine cortisol achievable with the Immulite 2000 Xpi cortisol immunoassay.

Determining a simple quality control (QC) rule for daily performance monitoring depends on the desired total allowable error (TEa) for the measurand. When no consensus TEa exists, the classical approach of QC rule validation cannot be used. Using the results of previous canine serum and urine cortisol validation studies on the Immulite 2000 Xpi, we applied a reverse engineering approach to QC rule determination, arbitrarily imposing sigma = 5, and determining the resulting TEa for the QC material (QCM; TEa) and the resulting probability of error detection (P) for each QC rule.

Evaluation of Sysmex XT-2000iV analyzer performance across a network of five veterinary laboratories using a commercially available quality control material.

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.

Validation study of canine serum cortisol measurement with the Immulite 2000 Xpi cortisol immunoassay.

We report the results of validation of canine serum cortisol determination with the Immulite 2000 Xpi cortisol immunoassay (Siemens), with characterization of precision (CV), accuracy (spiking-recovery [SR] bias), and observed total error (TEo = bias + 2CV) across the reportable range, specifically at the most common interpretation thresholds for dynamic testing. Imprecision increased at increasing rate with decreasing serum cortisol concentration and bias was low, resulting in increasing TEo with decreasing serum cortisol concentration. Inter-laboratory comparison study allowed for determination of range-based bias (RB) and average bias (AB).

Validation study of canine urine cortisol measurement with the Immulite 2000 Xpi cortisol immunoassay.

We report here validation of the Immulite 2000 Xpi cortisol immunoassay (Siemens; with kit lot numbers <550) for measurement of urine cortisol in dogs, with characterization of the precision (CV), accuracy (spiking-recovery [SR] bias), and observed total error (TEo = bias + 2CV) across the reportable range. Linearity assessed by simple linear regression was excellent. Imprecision, SR bias, and TEo increased markedly with decreasing urine cortisol concentration.

Comparison of serum and plasma SDMA measured with point-of-care and reference laboratory analysers: implications for interpretation of SDMA in cats.

Objectives: Symmetric dimethylarginine (SDMA) reflects the glomerular filtration rate (GFR) in people, dogs and cats. Initial assays used a liquid chromatography-mass spectroscopy (LC-MS) technique. A veterinary immunoassay has been developed for use in commercial laboratories and point-of-care (POC) laboratory equipment.

Analytical quality performance goals for symmetric dimethylarginine in cats.

Background: Symmetric dimethylarginine (SDMA) reflects the glomerular filtration rate (GFR) in people, dogs, and cats. Initial assays used a liquid chromatography-mass spectroscopy (LC) technique. A veterinary immunoassay has been developed for use in commercial laboratories and point-of-care (POC) laboratory equipment.