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.

Serum proteome profiles in cats with chronic enteropathies.

Background: Serum protein biomarkers are used to diagnose, monitor treatment response, and to differentiate various forms of chronic enteropathies (CE) in humans. The utility of liquid biopsy proteomic approaches has not been examined in cats.

Hypothesis/objectives: To explore the serum proteome in cats to identify markers differentiating healthy cats from cats with CE.

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.

Current and emerging concepts in biological and analytical variation applied in clinical practice.

A single laboratory result actually represents a range of possible values, and a given laboratory result is impacted not just by the presence or absence of disease, but also by biological variation of the measurand in question and analytical variation of the equipment used to make the measurement. Biological variation refers to variability in measurand concentration or activity around a homeostatic set point. Knowledge of biological and analytical variation can be used to facilitate interpretation of patient clinicopathologic data and is particularly useful for interpreting serial patient data and data at or near reference limits or clinical decision thresholds.

Biological variation of routine haematology and biochemistry measurands in the horse.

Background: Clinical pathology results are typically interpreted by referring to population-based reference intervals. The use of individualised (subject-based) reference intervals is more appropriate for measurands with a high degree of variation between individuals.

Objectives: To determine the biological variation of routinely analysed equine haematology and biochemistry measurands and calculate indices of individuality and reference change values which enable production of individualised reference intervals, in a group of healthy, privately owned horses.

Analytical quality goals-a review.

Analytical quality goals indicate how laboratory tests must perform to be clinically useful for their intended purpose. These goals have historically focused on analytical error assessment for quantitative methods and vary with measurand concentration or activity, and species. Although formalized quality goal models have been developed in human medicine, quality goals in veterinary medicine, to date, have not been formalized; use of human regulatory-based goals, consensus-based goals, or biologic variation-based goals have been reported most often.

Clinical application of biological variation data to facilitate interpretation of canine and feline laboratory results.

Interpretation of laboratory results is based on comparison of the patient's own results against established decision thresholds or reference intervals in the context of the clinical presentation and history. Blood measurand analysis has pre-analytical, analytical and physiological sources of variation, which may complicate interpretation of results. Biological variation describes the physiological random fluctuation of blood measurands around a homeostatic set point, which varies within and between individuals.

Recommendations for designing and conducting veterinary clinical pathology biologic variation studies.

The recent creation of a veterinary clinical pathology biologic variation website has highlighted the need to provide recommendations for future studies of biologic variation in animals in order to help standardize and improve the quality of published information and to facilitate review and selection of publications as standard references. The following recommendations are provided in the format and order commonly found in veterinary publications. A checklist is provided to aid in planning, implementing, and evaluating veterinary studies on biologic variation (Appendix S1).

Commutability and interchangeability of commercial quality control materials with feline plasma for common biochemical analytes.

Background: Species-specific plasma or serum pools are considered the ideal standard material for quality control materials (QCM) instead of commercially available human QCM. However, using plasma or serum pools is limited by volume restrictions, degradation over time, and a narrow range of analyte concentrations. Concentrations of QCM analytes should be consistent or commutable with those from species-specific plasma/serum samples, and the precision from plasma pools should be comparable or interchangeable with commercial human QCM.

Bias in feline plasma biochemistry results between three in-house analysers and a commercial laboratory analyser: results should not be directly compared.

In-house analysers are commonplace in small animal practices but cannot be calibrated by the operator; therefore, any bias in the generated plasma analyte values cannot be corrected. Guidelines such as grading of renal disease and published reference intervals (RIs) in veterinary textbooks assume plasma biochemistry values generated by different analysers are equivalent. This study evaluated the degree of bias, as well as if bias was constant or proportional, for feline plasma biochemical analytes assessed by three in-house biochemistry analysers compared with a commercial laboratory analyser.

Assessments of feline plasma biochemistry reference intervals for three in-house analysers and a commercial laboratory analyser.

For each species, the manufacturers of in-house analysers (and commercial laboratories) provide standard reference intervals (RIs) that do not account for any differences such as geographical population differences and do not overtly state the potential for variation between results obtained from serum or plasma. Additionally, biases have been demonstrated for in-house analysers which result in different RIs for each different type of analyser. The objective of this study was to calculate RIs (with 90% confidence intervals [CIs]) for 13 biochemistry analytes when tested on three commonly used in-house veterinary analysers, as well as a commercial laboratory analyser.

Successful treatment of a localised CDC Group EF-4a infection in a cat.

Organisms classified within the Center for Disease Control (CDC) Group eugonic fermenter (EF)-4a are facultative anaerobic, Gram-negative coccobacilli, thought to be of the family Neisseriaceae. CDC Group EF-4a is considered a component of normal oral flora in cats and dogs and is most commonly isolated from bite injuries of human patients. Most previously reported cases in cats have involved fatal necrotising pneumonia.

Disseminated Mycobacterium avium infection in young cats: overrepresentation of Abyssinian cats.

Disseminated Mycobacterium avium-intracellulare complex (MAC) infection was diagnosed in 10 young cats (1-5 years of age) from Australia or North America between 1995 and 2004. A further two cats with disseminated mycobacteriosis (precise agent not identified) were recognised during this period. Of the 12, 10 were Abyssinian cats, one was a Somali cat and one was a domestic shorthair cat.