Sixty adult and yearling female white-tailed deer (Odocoileus virginianus) were collected in July 2008 (n=30) and March 2009 (n=30) from eastern North Carolina as part of a population health assessment. During July 2008, standard serum analyses revealed hyperkalemia in all deer sampled. In March, the effect of processing time as a possible source of the hyperkalemia was investigated. For a subset of deer (n=10), blood tubes were centrifuged and processed at four time points (0, 30, 60, and 120 min) postcollection. Delayed centrifugation and plasma separation did not affect potassium (K ) concentration over time, indicating that a shift in intracellular K did not occur and the hyperkalemia was not due to improper sample handling. Potassium levels were negatively correlated with age and varied across collection periods. Also, K levels were positively correlated with glucose and not correlated with creatine kinase (CK). No single variable indicated a strong enough relationship to explain the hyperkalemia in the study.