PAIRED BIOCHEMICAL ANALYSIS OF PIGMENTED PLASMA SAMPLES FROM ZOO-KEPT AMERICAN FLAMINGOS (PHOENICOPTERUS RUBER) USING A POINT-OF-CARE AND A STANDARD WET CHEMISTRY ANALYZER

LACK OF AGREEMENT BETWEEN A POINT-OF-CARE BLOOD URIC ACID METER AND A BENCHTOP CHEMISTRY ANALYZER IN EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA)

Uric acid (UA) is excreted as an end product of protein metabolism in many reptiles, including some chelonians. Elevated plasma UA concentrations can occur due to many physiologic and pathologic changes, and determining plasma UA concentrations is part of a complete general health assessment in this taxon. UA concentrations are typically measured using benchtop chemistry analyzers, but point-of-care (POC) UA meters have also been developed for human use. However, these POC UA meters have not been investigated for use in any reptile species. The purpose of this study was to assess agreement between UA measurements produced by a standard benchtop chemistry analyzer and a POC UA meter in free-living eastern box turtles (Terrapene carolina carolina). UA concentrations were measured with a POC meter using fresh whole blood and frozen-thawed plasma and with a standard benchtop chemistry analyzer using frozen-thawed plasma. Poor-to-moderate agreement was present between each of the three methods as evidenced by mixed models, Passing-Bablok regression, Bland-Altman plots, and Cohen's κ. Differences between methods fell outside of clinically acceptable limits, indicating that the POC UA meter should not be used in eastern box turtles.

EVALUATION OF SYMMETRIC DIMETHYLARGININE AS AN ENDOGENOUS MARKER OF RENAL DISEASE IN GREATER FLAMINGOS (PHOENICOPTERUS ROSEUS)

Detection of renal disease in birds is currently reliant on biochemical measures such as uric acid, which is only elevated after significant renal compromise has occurred. Symmetric dimethylarginine (SDMA) production has not been previously evaluated in birds and no reference intervals (RI) for measurement exist in avian species. This study aimed to develop an RI for SDMA in greater flamingos (Phoenicopterus roseus) and evaluate the association between SDMA levels and renal disease. Blood from 60 flamingos was collected for RI development and the RI of SDMA was found to be 11.8-34.2 µg/dl. Symmetric dimethylarginine showed a strong positive correlation with uric acid, a moderate positive correlation with creatine kinase, and moderate negative correlations with total protein, albumin, and glucose. No correlation was found with pododermatitis score or body condition. Using the SDMA RI, six clinical cases were included for assessment of the clinical relevance of SDMA in renally compromised patients. All birds that were euthanized had elevated SDMA levels and severe renal or systemic pathology on necropsy.

Comparison of Hematocrit and Biochemical Analytes among Two Point-of-Care Analyzers (EPOC and i-STAT Alinity v) and a Veterinary Diagnostic Laboratory in the African Savanna Elephant (Loxodonta africana) and the Southern White Rhinoceros (Ceratotherium simum simum)

This study compared hematocrit measured with the EPOC and i-STAT Alinity v point-of-care analyzers and manual measurement of packed cell volume in managed African savanna elephants (Loxodonta africana) and southern white rhinoceros (Ceratotherium simum simum). Biochemical analytes were also measured with the EPOC, i-STAT Alinity v, and a veterinary diagnostic laboratory in the same animals. Analytes assessed included blood urea nitrogen, chloride, creatinine, glucose, ionized calcium, potassium, and sodium. There were no differences for hematocrit values for African savanna elephants or southern white rhinoceros (p ≤ 0.05). In African savanna elephants, there were no differences between the EPOC and i-STAT Alinity v analyzers for any measured analytes except ionized calcium. When compared to a veterinary diagnostic laboratory, there were differences for a majority of the biochemical analytes measured on the EPOC and i-STAT Alinity v analyzers in African savanna elephants. In southern white rhinoceros, there were differences for a majority of analytes among all three analyzers. While differences existed among the portable analyzers and a veterinary diagnostic laboratory for biochemical analytes in both species, these numerically small differences are unlikely to be clinically significant. For routine health care of African savanna elephants and southern white rhinoceros, these point-of-care analyzers may be a useful alternative to commercial analyzers for the parameters evaluated.

The Utility of Bile Acids for the Diagnosis of Liver Disease in Exotic Animals

The synthesis of bile acids occurs during the degradation of cholesterol in hepatocytes. Thus, this analyte is expected to be a sensitive indicator of hepatocellular dysfunction or alterations in portal circulation. Bile acids can be quantified via an enzymatic reaction to a highly conserved moiety across species. The evidence for the clinical utility of bile acids for the diagnosis of liver disease is strongest in birds and ferrets with equivocal evidence in rodents, rabbits, and reptiles. Current limitations to the interpretation of bile acids in exotic animal species include a paucity of species-specific reference intervals and incomplete understanding of bile acid metabolism in nonmammalian species and the diversity of bile acids synthesized by vertebrates.

REFERENCE VALUES AND COMPARISON OF BLOOD CHEMISTRY AND PLASMA PROTEIN VALUES BETWEEN GOLD STANDARD ANALYZERS AND FOUR POINT-OF-CARE DEVICES IN FREE-RANGING CANVASBACKS (AYTHYA VALISINERIA)

Accurate, timely, and cost-effective blood chemistry analysis is an essential tool for directing emergency treatment, monitoring the health status of captive and free-ranging individuals and flocks, and improving the efficacy of conservation actions. Blood samples were obtained from 52 canvasbacks (Aythya valisineria) that were captured on San Francisco Bay, California, during December 2017 as part of a long-term study. Reference values and clinical agreement were determined for blood chemistry and plasma protein parameters among four commonly used point-of-care devices (VetScan^® VS2, i-STAT^®, AlphaTRAK^®2 glucometer, refractometer) and two gold standard laboratory analyzers (Roche cobas^® c501, Helena SPIFE 3000 system). Canvasback reference values were generally within expected ranges for Anatidae species with the exception of higher upper limits for sodium and chloride. Creatine kinase and aspartate transaminase values exceeded a published threshold for diagnosis of capture myopathy even though study birds were captured using low-stress techniques and successfully released. With the exception of higher alkaline phosphatase in hatch-year canvasbacks, no age or sex differences were observed for any analyte in this population that was captured during a nonbreeding period. Analysis of analyzer agreement found raw VetScan aspartate transaminase, calcium, glucose, and uric acid values; corrected VetScan albumin, potassium, sodium, and total protein values; raw i-STAT glucose and potassium values; and corrected i-STAT sodium and chloride values were clinically interchangeable with Roche cobas values. Raw VetScan and i-STAT glucose values were also interchangeable. However, none of the Roche or point-of-care analyzer plasma protein values were in clinical agreement with gold standard electrophoresis values. The findings of this study highlight the need for analyzer- or technique-specific reference values and provide biologists and veterinarians quantitative reference values using currently available analyzers to better assess and respond to the health of individuals and populations.