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

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. Plasma biochemistry results from each POC analyzer were compared with the commercial laboratory analyzer using Bland-Altman difference plots and by determining whether the limits of agreement (LOAs) (95% of differences) fell within various quality goals after correcting for inherent bias.

RESULTS

Only 7 of 14 analytes on the Heska analyzer and 2 analytes on the IDEXX analyzer attained the most stringent LOA quality goal, which was being within desirable total error based on biologic variation (TEdes). The number of analytes achieving quality goals increased with less stringent standards such as American Society of Veterinary Clinical Pathologists allowable total error (ASVCP TEA) guidelines or if <95% of clinical comparisons reaching these quality goals is considered acceptable. Widespread bias was found between both POC analyzers and the commercial laboratory analyzer.

CONCLUSIONS

The performance of both POC biochemistry analyzers was variable compared with a commercial laboratory analyzer. Performance goals were only able to be attained after the bias for each analyzer was accounted for by offsetting the LOAs and quality goals set by the mean bias for each analyte on each analyzer.

Haematological and biochemical reference intervals in healthy Ragdoll cats

OBJECTIVES

Breed-specific reference intervals (RIs) may be necessary to avoid misinterpretation of laboratory results. The main aim of this study was to establish haematobiochemical RIs for Ragdoll cats.

METHODS

Forty-two clinically healthy adult (0.8-10 years old) Ragdoll cats (Ragdoll population [RP]) and 60 non-Ragdoll cats as the control population (CP) were prospectively enrolled. Results of haematology, biochemistry and total thyroxine (TT4) were used to determine both Ragdoll-specific and general feline population RIs for each variable using Reference Value Advisor software according to the Clinical and Laboratory Standards Institute guidelines and the American Society of Veterinary Clinical Pathology guidelines.

RESULTS

For each analyte, RIs of the RP were calculated and compared with those obtained from the CP. Haematocrit, haemoglobin, mean cell volume, mean cell haemoglobin concentration, reticulocyte absolute count, platelet count and lymphocyte absolute number were statistically different from the CP. Biochemistry RIs revealed a statistical difference in creatinine kinase (CK), total protein, urea, creatinine, glucose, total calcium and iron.

CONCLUSIONS AND RELEVANCE

Haematobiochemical RIs of the general feline population must be used with caution in Ragdoll cats when it comes to iron and glucose concentrations, CK activity and absolute lymphocyte number. For these parameters, the use of breed-specific RIs is suggested. The docile and more relaxed nature of this breed may explain these differences and further investigations are necessary to better understand the results. Furthermore, investigations are needed to evaluate the possible benefits of breed-specific urea RIs.

Reference Intervals for Selected Hematology and Clinical Chemistry Measurands in Temminck's Pangolin (Smutsia temminckii)

Pangolins are the world's most trafficked non-human mammals. A significant number of Temminck's pangolins (Smutsia temminckii) are presented for veterinary care and rehabilitation in southern Africa. Little is known about the physiology and normal health of this species, making diagnosis and medical management difficult. This study aimed to establish reference intervals (RIs) for hematology and plasma clinical chemistry in the Temminck's pangolin. RIs were generated according to international guidelines using samples from 27 healthy free-living (n = 18) and rehabilitated (n = 9) pangolins. Hematology was performed using the Abaxis VetScan HM5 analyzer with manual differentials; clinical chemistry was performed using heparin plasma on the Abaxis VetScan VS2 and Cobas Integra 400 Plus analyzers. Hematology RIs were: RBC 3.88-8.31 × 10¹²/L, HGB 73-150 g/L, HCT 26-51%, MCV 59-72 fL, MCH 15.6-21.4 pg, MCHC 257-325 g/L, RDW 14.3-19.1%, WBC 1.80-10.71 × 10⁹/L. Vetscan VS2 clinical chemistry RIs were: albumin 27-41 g/L, ALP 26-100 U/L, ALT 25-307 U/L, amylase 267-826 U/L, bilirubin 4-10 μmol/L, calcium 2.1-2.2 mmol/L, globulin 21-55 g/L, glucose 3.8-10.0 mmol/L, phosphate 1.3-2.6 mmol/L, potassium 3.6-5.9 mmol/L, sodium 132-140 mmol/L total protein 52-84 g/L, and urea 5.3-11.4 mmol/L. RIs for creatinine were not calculated as analytical imprecision exceeded analytical performance goals. Cobas Integra clinical chemistry RIs were: albumin 22-33 g/L, ALP 20-104 U/L, ALT 17-291 U/L, amylase 466-1,533 U/L, bilirubin 1-14 μmol/L, calcium 2.0-2.4 mmol/L, creatinine <58 μmol/L, globulin 23-49 g/L, glucose 3.6-10.1 mmol/L, phosphate 1.0-2.2 mmol/L, potassium 3.1-5.8 mmol/L, sodium 137-150 mmol/L, total protein 47-72 g/L, and urea 6.0-12.5 mmol/L. There was significant bias between the two chemistry analyzers for several measurands. Differences were found for some analytes between free-living and rehabilitated animals, probably reflecting differences in nutrition and hydration. These are the first RIs generated for Temminck's pangolin. These results will allow veterinarians to better determine pangolin health status, formulate optimal treatment plans and increase patient survival rates in this endangered species.

Electrolyte measurements differ between point-of-care and reference analysers in dogs with hypoadrenocorticism

INTRODUCTION

Dogs treated for hypoadrenocorticism are monitored through analysis of their blood electrolytes. This is routinely performed with point-of-care analysers and doses of medications are adjusted based on the results.

OBJECTIVES

To investigate the performance of two point-of-care analysers (IDEXX Catalyst Dx and IDEXX VetStat) against a reference laboratory method for the measurement of blood sodium, potassium and chloride concentrations, as well as sodium: potassium ratios, in dogs diagnosed with and treated for hypoadrenocorticism.

METHODS

Forty-eight dogs were enrolled into a prospective cross-sectional study. Paired blood samples were taken and tested on two point-of-care analysers and at a reference laboratory. Statistical analysis was then performed with Bland-Altman analysis and Passing-Bablok regression. The clinical effects of inaccurate electrolyte analysis were investigated.

RESULTS

In total, 329 samples were tested on the Catalyst analyser, while another 72 samples were tested on the VetStat. Passing-Bablok regression identified both proportional and constant bias for some analytes. There was poor agreement between sodium and chloride concentrations on both analysers. Both analysers tended to give higher results than the reference method for all analytes, except for potassium when measured on the VetStat.

CLINICAL SIGNIFICANCE

There are inherent differences between the electrolyte concentrations measured by these two point-of-care analysers and reference laboratory methods in dogs with hypoadrenocorticism.

Predictive Blood Chemistry Parameters for Pansteatitis-Affected Mozambique Tilapia (Oreochromis mossambicus)

One of the largest river systems in South Africa, the Olifants River, has experienced significant changes in water quality due to anthropogenic activities. Since 2005, there have been various “outbreaks” of the inflammatory disease pansteatitis in several vertebrate species. Large-scale pansteatitis-related mortality events have decimated the crocodile population at Lake Loskop and decreased the population at Kruger National Park. Most pansteatitis-related diagnoses within the region are conducted post-mortem by either gross pathology or histology. The application of a non-lethal approach to assess the prevalence and pervasiveness of pansteatitis in the Olifants River region would be of great importance for the development of a management plan for this disease. In this study, several plasma-based biomarkers accurately classified pansteatitis in Mozambique tilapia (Oreochromis mossambicus) collected from Lake Loskop using a commercially available benchtop blood chemistry analyzer combined with data interpretation via artificial neural network analysis. According to the model, four blood chemistry parameters (calcium, sodium, total protein and albumin), in combination with total length, diagnose pansteatitis to a predictive accuracy of 92 percent. In addition, several morphometric traits (total length, age, weight) were also associated with pansteatitis. On-going research will focus on further evaluating the use of blood chemistry to classify pansteatitis across different species, trophic levels, and within different sites along the Olifants River.