Measurement of the α1 (fast liver) fraction of alkaline phosphatases in the serum for 217 cancer patients, 92 patients with nonmalignant hepatic affections and 131 controls, revealed that the α1 fraction offers better global value (94%), sensitivity (96%), and specificity (93%) than γGT or total alkaline phosphatase determinations for the detection of liver metastases during cancer. Initial data from study of the time of appearance of the α1 fraction reveals that this fraction shows up earlier than rises in the γGT or total alkaline phosphatases. Results of a multiparametric study conducted on the α1 fraction and various hepatic enzymatic tests (SGOT, SGPT, GLDH, ALP, γGT) indicate that the α1 fraction used alone is better than any other test or combination of tests for biological detection of liver metastases. As concerns the influence of chemotherapy on the appearance of the α1 fraction, the majority of the drugs used for anticancer chemotherapy do not seem to affect measurement of the α1 ALP fraction. The α1 fast liver fraction of alkaline phosphatases, detected by electrophoresis on cellulose acetate, can be considered one of the best known tests for the detection of liver metastases. Cancer 52:140‐145, 1983.