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

Abstract

OBJECTIVE To determine (1) the relationship, (2) the difference, and (3) the diagnostic discordance between blood total calcium concentration (tCa) and ionized calcium concentration (iCa) in a population of client-owned chelonian patients. ANIMALS 161 consecutively admitted client-owned chelonians. PROCEDURES Results for tCa, iCa, and other variables were extracted from records. Bound calcium concentration (tCa – iCa) was calculated. General linear models were developed to evaluate factors affecting tCa, iCa and bound calcium concentrations. Diagnostic discordance between tCa and iCa was assessed. RESULTS iCa decreased with increasing albumin concentration, it was not influenced by sex, and it was lower in chelonians with disorders of the reproductive tract than in those with disorders of the endocrine/hemopoietic and urinary systems. Total calcium and bound calcium concentrations increased with increasing albumin concentration; they were higher in females and in chelonians with disorders of the reproductive tract. Of the 161 chelonians, 93 (57.7%; 95% CI, 49.7% to 65.5%) would have had a different diagnosis of calcium status based on tCa and iCa results (ie, diagnostic discordance). A 2.2 mmol/L cutoff value for bound calcium could differentiate chelonians with and without disorders of the reproductive tract with a sensitivity (95% CI) of 81.8% (64.5% to 93.0%) and specificity of 76.4% (68.0% to 83.5%). CLINICAL RELEVANCE tCa and iCa were related and were associated with albumin concentrations in chelonians. Evaluation of tCa or iCa alone is likely to result in underdiagnosis of alterations of the calcium status. Calculation of bound calcium concentration could help identify chelonians with reproductive disorders.

Association between glomerular filtration rate and plasma N‐terminal pro‐atrial natriuretic peptide concentration in dogs

“…All independent variables were checked for multicollinearity using the variance inflation factor (VIF). Interactions between predictors were included and tested in the final model and retained if they contributed to the model fit (Girolamo 2022). Akaike Information Criterion (AIC) values were used to compare the models containing different predictors.…”

Providing expert insight into clinical practice

“…Di Girolamo 9 analyzes whether calcium concentrations in chelonians are associated with each other or with values for other analytes, such as serum albumin concentration. He also reports, for chelonians with abnormalities in serum calcium concentration, which organ systems are most likely to be affected (spoiler alert: this is the uroGENITAL supplement!…”