False low blood sugar readings in a lamb with Mycoplasma ovis

Abstract

BACKGROUND: A 35-day-old male lamb with Mycoplasma ovis infection (previously Eperythrozoon ovis) was evaluated because of severe hypoglycemia (serum glucose 4 mg/dL, Hitachi 704 automated chemistry analyzer) inconsistent with the animal's condition. Whole blood glucose concentration measured with a glucometer was 74 mg/dL. OBJECTIVE: The purpose of this study was to investigate this discrepancy through in vitro evaluation of the patient's blood. METHODS: Blood was incubated alone, with increasing concentrations of plasma, or with equine serum of known glucose concentration for 0, 15, 30, and 60 minutes at room temperature; end-point glucose concentrations were compared with blood from a control sheep handled similarly. RESULTS: A rapid decline in glucose concentration was observed in heparinized or EDTA anticoagulated whole blood from the infected lamb incubated alone or with the equine serum. Glucose concentrations in incubated samples from a control sheep remained stable. Incubation of increasing concentrations of heparinized blood with autologous plasma resulted in decreased glucose concentrations in patient, but not control, blood. As parasitemia decreased after treatment, serum glucose concentration increased, serum lactate concentration decreased, and in vitro glucose concentration stabilized. CONCLUSIONS: These findings are consistent with parasite-associated in vitro glucose consumption. An increase in the lamb's plasma glucose concentration associated with reduction of parasite load suggested excess glucose consumption also may have occurred in vivo.