RESUMO
Objective To investigate the feasibility of L-[1- 13 C]phenylalanine breath test to assess liver function and determine the effective parameters of the test for quantitative assessment of liver function in adult. Methods Twelve healthy volunteers served as control group, and 26 liver cirrhotic patients with hepatitis B were divided into three groups, 10 patients in Child-Pugh classification A, 8 in B and 8 in C, An oral dose of 100 mg of nonradiative tracer L-[1- 13 C]phenylalanine were administered to all the subjects. Breath samples were taken before and different intervals within 360 min after administration. 13 CO_2 enrichment was measured by isotope ratio mass spectrometer. Results After the oral administration of L-[1- 13 C] phenylalanine, 13 C excretion reached a peak within 10-30 min. The parameters of 13 CO_2 excretion rate at 30 min ( 13 CO_2ER_ 30 ) , 13 C cumulative excretion of 60 min ( 13 C_ cum60 ), 75 min( 13 C_ cum75 ), 90 min( 13 C_ cum90 ) and 13 CO_2 half excretion time ( t _ 1/2 ) were shown sensitive, which could differentiate significantly the groups( P