Estimation of14C-Triolein Assimilation as a Test of Lipid Assimilation

Abstract

Two tests of lipid assimilation based on estimation of ¹⁴C-triolein assimilation from expiratory ¹⁴CO₂ (breath test) and from serum radioactivity of ¹⁴C, respectively, were investigated in 48 consecutive patients suspected of having malassimilation. Patients with proven malassimilation had significantly lower expiration of ¹⁴CO₂ and lower serum radioactivity of ¹⁴C than patients with normal lipid assimilation. The se-¹⁴C test correctly diagnosed significantly more patients with malassimilation than the breath test; the diagnostic efficiencies were 0.87 and 0.74, respectively. The results of both tests correlated with measurement of faecal fat. However, within the group of patients with proven malassimilation the results of the breath test correlated poorly with faecal fat, whereas a significant correlation was found between the se-¹⁴C test and faecal fat within this group. Correspondingly, the correlation between the results of the breath test and the se-¹⁴C test was poor, indicating that intermediate metabolism influences the results.