Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (815 page)

   Severe pernicious anemia (PA), aplastic anemia

   Cirrhosis

   CHF (causing liver disease)

   Hepatic carcinoma

   Malnutrition

   Acute infections and burns

   AMI, pulmonary embolism

   Muscular dystrophy

   After surgery

   Chronic renal disease

   Limitations

   PChE levels are not to be confused with AChE levels. PChE levels are earlier indicators than AChE levels of organophosphate exposure.

   Patients with normal PChE activity show 70–90% inhibition by dibucaine, whereas patients homozygous for the abnormal allele show little or no inhibition (0–20%) and usually low levels of enzyme. Heterozygous patients have intermediate PChE levels and response to inhibitors.

   Dibucaine inhibition is no value over total PChE, for the diagnosis of organophosphorus pesticide exposure.