Reading the results

Arrange a plain abdominal X-ray on day seven to determine the location and extent of elimination of the radiopaque markers. The distribution of markers in the various colonic segments (i.e. caecum-ascending colon, transverse colon, descending colon and sigmoid colon-rectum*) can provide information about the type of delay.

Colonic transit time is calculated as the mean oro-anal transit time (OATT, mouth-to-anus) for the daily marker doses swallowed. With a daily dose of ten (10) markers, the transit time in days is M divided by 10, i.e. the number of markers counted from the X-ray film (M) divided by the daily dose.

A different shape of the markers is used on day six to assist in localization of cecum and the division of the day 6-dose into a morning and an evening dose will enhance precision in measuring rapid transit.

With ten (10) markers per day each marker is equivalent to 0.1 days or 2.4 hours (i.e. 2.4 hours per marker). The formula that is used with the Transit-Pelletsmethod™ (M/10) will provide a result on both total- and segmental transit time in days. Some clinics prefer to present the result in hours and if so, the formula Mx2.4 can be used on both total- and segmental transit time. It is up to the individual clinic which formula they prefer to use.

* The most commonly used principle in Scandinavia, but also very common outside Scandinavia, is to divide the colon into four segments, i.e. caecum-ascending colon, transverse colon, descending colon and sigmoid colon-rectum.

Colonic transit time (OATT); reference values

Normal transit time corresponds to the range from percentile 5 to percentile 95 in the control material. Reference values based on 199 subjects: 1) Abrahamsson et al, Scand J gastroenterol 1988 Suppl 152:72-80; 2) Sadik et al, Scand J Gastroenterol 2003, 38:36-42; 3) Törnblom et al, data on file, Gastrointest Lab, Sahlgrenska Univ. Hospital.

Segmental transit time; upper reference values

Segmental transit times: Abrahamsson et al, Scand J Gastroenterol 1988 Suppl 152:72-80. Percentile 95 calculated per segment in healthy subjects.