Separate estimation of intestinal and liver fractions of blood serum alkaline phosphatase in patients with acute forms of impairments corroborated the tissue specificity of these isoenzymes and showed the stable character of alterations in their activity at the initial steps of inflammatory-destructive processes in liver tissue, bile and intestinal tracts. The express methods for estimation of blood serum alkaline phosphatase isoenzymes enabled to carry out the examination within 1.5-2 hrs; the diagnostic methods may be widely used in urgent abdominal surgery.