When doctors suspect disease in a deep-seated vital organ, e.g., the heart or liver, it may be dangerous or downright impossible to take a tissue sample (biopsy specimen) for microscopic examination. Biochemistry may supply a neat if not simple solution, says Dr. Felix Wróblewski of Manhattan's Sloan-Kettering Institute. Instead of cutting for a tissue sample, it may be enough for the doctor to get a little blood from the patient and analyze its enzymes.
Dozens of chemically complex enzymes serve the body as catalysts, usually in minute quantities. In disease, the relative concentration of...