Clinical significance of the radioisotope test using 131I labelled serum albumin for evaluating the peripheral circulation in the foot during a period of reactive hyperemia

The radioisotope test using 131I labelled serum albumin, performed during a period of reactive hyperemia, provides quantitative data which express the rate at which radioactive blood flowing from the leg replaces the non-radioactive blood present in the foot. It has been applied in normal subjects and in patients with arterial occlusions in the lower limbs. High washout rates, i.e. small M/2 index values, were found in the former, whereas low washout rates with higher M/2 indices were observed in the latter. Surprisingly, patients with a very low washout rate could be without subjective symptoms. The usefulness of the test in clinical practice is explained