OBJECTIVE To determine the correlation between glucose concentrations in serum, plasma, and blood measured by a point-of-care glucometer (POCG) and serum glucose concentration measured by an automated biochemical analyzer (ABA; gold standard). SAMPLE 152 canine and 111 feline blood samples. PROCEDURES For each sample, the glucose concentration in serum, plasma, and blood was measured by a POCG and compared with the ABA-measured glucose concentration by means of the Lin concordance correlation coefficient. Results were summarized by species for all samples and subsets of samples with hyperglycemia (ABA-measured glucose concentration > 112 mg/dL for dogs and > 168 mg/dL for cats) and pronounced hyperglycemia (ABA-measured glucose concentration > 250 mg/dL for both species). The effect of PCV on correlations between POCG and ABA measurements was also assessed. RESULTS Hyperglycemia and pronounced hyperglycemia were identified in 69 and 36 canine samples and 44 and 29 feline samples, respectively. The POCG-measured glucose concentrations in serum, plasma, and blood were strongly and positively correlated with the gold standard concentration. The PCV was positively associated with the correlation between the POCG-measured blood glucose concentration and the gold standard concentration but was not associated with the correlations between the POCG-measured glucose concentrations in serum and plasma and the gold standard concentration. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that POCG-measured glucose concentrations in serum, plasma, and blood were strongly correlated with the ABA-measured serum glucose concentration, even in hyperglycemic samples. Given the time and labor required to harvest serum or plasma from blood samples, we concluded that blood was the preferred sample type for use with this POCG.