Background: In the Clonidine stimulation test (CST) for growth hormone (GH) deficiency GH is sampled five times after oral Clonidine administration.
Aim: To determine feasibility of reducing sample number.
Methods: We retrospectively analyzed CSTs from 250 consecutive patients (mean age 9.72±3.59, range 0.08-19.41 years). By protocol, GH was sampled at 0`, 30`, 60`, 90`, and 120`. GH deficiency (GHD) was diagnosed if peak GH was < 7.5 mcg/l in the CST and in a second (glucagon) stimulation test. We analyzed the importance of each sample in the CST towards diagnosis. Results: The most common peak times were 30, 60 and 90 min (81.6%). The 120` sample was the only one over 7.5 mcg/l in one CST (see shaded box below)
Conclusion: The 120 minute sample is superfluous as it altered results in only 1/250 (0.4%) of CSTs.
