The diagnostic value of early 99mTc-HMPAO-leukocyte images (2 min, 0.5 hr, 2 hr and 4 hr) was studied in 87 prospectively performed investigations in 80 patients with a suspicion of abdominal inflammation or infection. Sensitivity, specificity and accuracy were 74%, 85% and 77% in the 2-min scans, 88%, 81% and 86% in the 0.5-hr scans, 95%, 85% and 92% in the 2-hr scans, and 96%, 92% and 95% in the 4-hr scans. Nonspecific bowel accumulation was seen in 7% of patients at 2 hr and in 28% at 4 hr but was easily distinguishable from pathologic activity. The uptake in early images represents an active accumulation of granulocytes at the site of inflammation rather than nonspecific blood-pool activity judged by results of 99mTc-HMPAO-RBC imaging. We found that imaging within 2 hr from injection has a high diagnostic value, and that the activity accumulates in areas of infection and inflammation faster than in the intestinal background.