Evaluation of women with possible appendicitis using technetium-99m leukocyte scan

The authors evaluated the use of technetium-99m albumin colloid white blood cell (TAC-WBC) scan in women with possible appendicitis. One hundred and nine women underwent 110 TAC-WBC scans. One woman had a second scan on a separate admission and was considered two individual patients in the analysis. Twenty-six women had appendicitis, 10 of whom had a perforated appendix at surgery. The TAC-WBC scan was indeterminate (abnormal but nondiagnostic for appendicitis) in 52 women (47%), nine of whom had appendicitis. Fifty-eight scans were read as positive or negative for appendiceal pathology. There were 16 true positives, 5 false positives, 36 true negatives, and 1 false negative. The predictive value of a positive scan was 76%, and the predictive value of a negative scan was 97%. The TAC-WBC scan was positive in 62% of patients with appendicitis and negative in 43% of the patients without appendicitis resulting in an overall accuracy of 47% in the 109 women. The main value of TAC-WBC scan in women with possible appendicitis is its high negative predictive value and the main problem with the TAC-WBC scan is its high indeterminate rate.