In human and small animal medicine, hyperglycemia and hypoglycemia are common hematologic abnormalities. Treatment for either condition requires serial measurements of blood glucose concentrations with near instantaneous results. Therefore, POC devices that require a minimal amount of blood for measurement of glucose concentration are essential. The introduction of reliable, inexpensive, and accurate handheld POC blood glucose meters has greatly facilitated the treatment of humans,1 cats, and dogs2 with abnormalities in blood glucose concentrations. The routine use of such meters has been made possible through studies3–5 in which use of POC instruments has been validated in the relevant species.
Abnormalities in glucose regulation are not believed to be as common in avian species as they are in mammals.6 Nevertheless, hyperglycemia secondary to diabetes, stress, and steroid hormones has been reported.7 Hypoglycemia in many species is associated with starvation, liver disease, aspergillosis, and sepsis.6,7 The inability to obtain values for blood glucose concentration in a timely, cost-effective manner has made use of blood glucose concentrations problematic in the treatment of pet birds. Typically, measurement of blood glucose concentrations in birds requires sending serum samples to a central laboratory or the use of specialized chemistry analyzers. The associated cost and time have limited the usefulness of measuring blood glucose concentrations in critically ill birds.
Two different technologies are commonly used in POC blood glucose meters: amperometric and colorimetric. With amperometric devices, glucose in the subject's blood reacts with glucose oxidase or glucose dehydrogenase to produce an anodic current. The meter measures the resulting current and converts it into a glucose concentration that is displayed on the unit's liquid crystal display. In these units, the correct amount of blood is automatically drawn into the hollow portion of a test strip, where the reaction takes place. With colorimetric devices, the correct amount of blood (typically 1.5 μL) is automatically drawn into the hollow portion of a test strip, where the blood glucose is oxidized, resulting in a color change. The degree of change is dependent on the concentration of glucose in the blood and is read by use of reflectance photometry. This information is then translated into a glucose concentration that is displayed on the unit's liquid crystal display.
A study8 revealed that handheld, POC blood glucose meters consistently underestimate blood glucose concentrations in rhinoceros auklets, thus making the meters useful only as a screening device. To the authors' knowledge, no study to date has evaluated the validity of POC blood glucose meters for use in psittacines, which are commonly kept as pets. The purpose of the study reported here was to determine the degree of agreement between 3 commercially available POC blood glucose meters and a laboratory analyzer for measurement of blood glucose concentrations in Hispaniolan Amazon parrots (Amazona ventralis).
Limits of agreement
Microtainer, Becton-Dickinson, Franklin Lakes, NJ.
Accu-Check, Roche Diagnostics, Mannheim, Germany.
OneTouch Ultra, LifeScan Inc, Milpitas, Calif.
Reli On Ultima, Solartek Products, Alameda, Calif.
Olympus AU640e chemistry analyzer, Olympus America, Center Valley, Pa.
MedCalc, version 18.104.22.168, MedCalc Software, Mariakerke, Belgium.
GraphPad Prism, version 5.0 for Macintosh, GraphPad Software Inc, San Diego, Calif.
Reusch C, Wess G, Casella M. Home monitoring of blood glucose concentration in the management of diabetes mellitus. Compend Contin Educ Pract Vet 2001;23:544–557.
Wess G, Reusch C. Evaluation of five portable blood glucose meters for use in dogs. J Am Vet Med Assoc 2000;216:203–209.
Wess G, Reusch C. Assessment of five portable blood glucose meters for use in cats. Am J Vet Res 2000;61:1587–1592.
Johnson RN, Baker JR. Accuracy of devices used for self-monitoring of blood glucose. Ann Clin Biochem 1998;35:68–74.
Hochleithner M. Biochemistries. In: Ritchie B, Harrison G, Harrison L, eds. Avian medicine. Lake Worth, Fla: Wingers, 1994;223–245.
Lieske C, Ziccardi M, Mazet J, et al. Evaluation of 4 hand held blood glucose monitors for use in seabird rehabilitation. J Avian Med Surg 2002;16:277–285.
Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986;1:307–310.
Tang Z, Lee JH, Louie RF, et al. Effects of different hematocrit levels on glucose measurements with handheld meters for point-of-care testing. Arch Pathol Lab Med 2000;124:1135–1140.