In this study, hematologic and biochemical reference values for the critically endangered kakapo (Strigops habroptilus) were evaluated to assess the effect of blood storage, processing, and collection on interpretation of these values. The medians and variances of hematologic and biochemical parameters measured from samples collected from kakapo in 1996 and 2002 were compared. Differences in the handling and processing of samples between the 2 sampling periods contributed to significant differences in the medians for packed cell volume, hemoglobin, total protein, aspartate aminotransferase, alkaline phosphatase, phosphorous, and creatinine. The effect of separating plasma from the cellular components of the blood at either 3.5 or 36 hours after collection was studied by using paired blood samples. Increased time between collection and separation significantly affected median concentrations of glucose, calcium, creatine kinase, alkaline phosphatase, aspartate aminotransferase, and lactate dehydrogenase. Gender had no significant effect on parameter medians or variances. The results of this study highlight the limitations of using reference values in wildlife medicine, where ideal collection and handling of samples in field studies may be compromised and prevent accurate interpretation of test results. Tables of hematologic and biochemical parameters means, standard deviations, plus minimum and maximum values obtained from this small population are provided for application in future health monitoring of the kakapo.