All but trivial pit viper bites require A baseline complete blood count (including platelets) Coagulation profile (eg, prothrombin time, partial thromboplastin time, fibrinogen) Measurement of fibrin degradation products Urinalysis Measurement of serum electrolytes, blood urea nitrogen, and creatinine For moderate and severe envenomations, patients require blood typing and cross-matching, ECG, chest x-ray, and creatine kinase tests, as governed by the patient's status, often as frequently as every 4 hours for the first 12 hours and then daily.