Comparison of Dilution on Eastern Box Turtle (Terrapene carolina carolina) and Marine Toad(Rhinella marinus) Blood Parameters as Measured on a Portable Chemistry Analyzer

Abstract

Biochemical testing is an important clinical tool in evaluating the physiology of reptiles and amphibians. Suitable point of care analyzers can allow for rapid delivery of results, but small patient size can inhibit sufficient sample collection. This study evaluated the utility of sample dilution with sterile distilled water as a means of biochemical evaluation when sample volume is limited. Blood was collected from 12 eastern box turtles (Terrapene carolina carolina) and 12 marine toads (Rhinella marinus) and analyzed via i-STAT CHEM8+ cartridges. Two undiluted samples and two samples diluted 1 : 1 with sterile water were evaluated immediately following collection for each animal in the study. Analytes reported in the diluted samples were limited to glucose, ionized calcium, and total carbon dioxide. The expected dilution ratio value of diluted to undiluted samples was 0.5, of which glucose in both turtles and toads was nearest. Dilution ratio values for ionized calcium, however, were higher than expected in both turtles and toads. Sample dilution is not recommended for most analytes included on the CHEM8+ cartridge due to values occurring outside the limits of detection for the analyzer. Glucose and ionized calcium values obtained on diluted samples should be interpreted with caution but may provide clinical utility in reptile and amphibian patients where sample volume is limited.

Relationship, difference, and diagnostic discordance between blood ionized and total calcium concentrations in client-owned chelonians

“…Diagnostic discordance-Each chelonian was categorized as having a normal, low, or high iCa concentration and normal, low, or high tCa concentration based on a priori determined cutoffs. The primary cutoffs for ionized and tCa concentrations were arbitrarily decided before performing the analysis based on a number of previous studies 26,[28][29][30][31][32] on nonmarine chelonians, and they reflect the current reference intervals used by the author for chelonians. The primary cutoffs were 1.2 to 1.6 mmol/L and 10 to 14 mg/dL for iCa and tCa, respectively.…”

“…Further studies focused on the impact of correction formulas in chelonians are necessary to answer this clinical question. Second, primary cutoffs were chosen for determination of diagnostic discordance on the basis of the reference intervals currently in use by the author and multiple articles, 26,[28][29][30][31][32] rather than cutoffs for each individual species. Different individual articles in chelonians provide different reference intervals for circulating analytes.…”

Hematology and Biochemistry of the Española Lava Lizard (Microlophus delanonis)

“…Anion gap and hemoglobin were calculated by the i-STAT analyzer. The i-STAT analyzer has been previously validated for field sample processing in multiple reptilian species such as the bearded dragon ( Pogona vitticeps ), the eastern box turtle ( Terrapene carolina carolina ), the Galápagos marine iguana ( Amblyrhynchus cristatus ), the San Cristóbal Galápagos tortoise ( Chelonoidis chathamensis ), and the San Cristóbal lava lizard (Christiansen et al ., 2013; Lewbart et al ., 2015, 2018; Arguedas et al ., 2018; Griffioen et al ., 2020).…”

Analysis of Circulating Fatty Acid Profiles in Free-Ranging and Managed Care Marine Toads (Rhinella marina) with a Comparison of Whole-Blood Vial and Whole-Blood Dried Blood Spot Card Analyses

“…Population control programs have been used to manage the impact of this invasive species and toads in this trial were collected as part of a population control program to be humanely euthanized. Thus, biological samples from these animals were collected to gather data as a potential amphibian model similar to prior publications [23][24][25][26][27][28]. The objectives of the current study were to: (1) report novel values of known circulating fatty acids in the marine toad as a potential model for anuran species; (2) compare marine toad fatty acid profiles of free-ranging (FR) animals to those in MC for 60 days; and (3) compare the analysis of DBS fatty acid samples to traditionally collected whole-blood samples in marine toads.…”