Assessment of colorectal transit by radiopaque marker excretion -A Sri Lankan study

Abstract

INTRODUCTION: Information about colorectal transit is obtained by counting ingested radiopaque markers on plain abdominal x-ray films. A person who expels at least 80% of the ingested markers by day 5 is considered to have a normal colonic transit time. Diet and lifestyle have a significant influence on colonic transit time. Therefore the diagnosis of normal or delayed transit based on values obtained in the West may not be appropriate for the Asian population METHOD: Thirty four healthy male volunteers were recruited to the study. Informed consent was obtained from all the volunteers prior to the study. They were on a normal Sri Lankan diet (rice with vegetable curry and fish/meat curry) prior to and during the study without any fibre supplements. They carried out their routine daily activities during the study. Each subject swallowed a radiopaque marker capsule (SITZMARK, USA) containing 24 radiopaque rings at 9.00am with a glass of water. The day of marker ingestion was taken as day 0. Starting from day 1, plain abdominal x-rays were taken daily, at 9.00am, till all the markers were excreted. RESULTS: Thirty three (33) subjects completed the study. The mean age of the subjects was 38 (range 27-46) yrs. None of the subjects reported any alteration in their bowel habits during the study. The number of markers remained in the abdomen each day after ingestion: day 1 - mean 3.10 (SD 6.3), day 2 - mean 0.88 (SD 2.5), day 3 - mean 0.28 (SD 0.7), day 4 - mean 0.00 (SD 0.0). By day 3 all the subjects excreted more than 21 (87.5%) ingested markers. CONCLUSION: Colonic transit is unlikely to be delayed If a Sri Lankan male expels more than 85% of the ingested markers by day 3.