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Open Access Research article

Clinical research on liver reserve function by 13C-phenylalanine breath test in aged patients with chronic liver diseases

Gan-sheng Zhang1, Zhi-jun Bao1*, Jian Zou1, Shu-ming Yin1, Yi-qin Huang1, Hai Huang1 and De-kai Qiu2

Author Affiliations

1 Department of Gastroenterology, Huadong Hospital, Fudan University, Shanghai 200040, China

2 Department of Gastroenterology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai Institute of Digestive Disease, Shanghai 200001, China

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BMC Geriatrics 2010, 10:23  doi:10.1186/1471-2318-10-23

Published: 12 May 2010



The objective of this study was to investigate whether the 13C-phenylalanine breath test could be useful for the evaluation of hepatic function in elderly volunteers and patients with chronic hepatitis B and liver cirrhosis.


L-[1-13C] phenylalanine was administered orally at a dose of 100 mg to 55 elderly patients with liver cirrhosis, 30 patients with chronic hepatitis B and 38 elderly healthy subjects. The breath test was performed at 8 different time points (0, 10, 20, 30, 45, 60, 90, 120 min) to obtain the values of Delta over baseline, percentage 13CO2 exhalation rate and cumulative excretion (Cum). The relationships of the cumulative excretion with the 13C-%dose/h and blood biochemical parameters were investigated.


The 13C-%dose/h at 20 min and 30 min combined with the cumulative excretion at 60 min and 120 min correlated with hepatic function tests, serum albumin, hemoglobin, platelet and Child-Pugh score. Prothrombin time, total and direct bilirubin were significantly increased, while serum albumin, hemoglobin and platelet, the cumulative excretion at 60 min and 120 min values decreased by degrees of intensity of the disease in Child-Pugh A, B, and C patients (P < 0.01).


The 13C-phenylalanine breath test can be used as a non-invasive assay to evaluate hepatic function in elderly patients with liver cirrhosis. The 13C-%dose/h at 20 min, at 30 min and cumulative excretion at 60 min may be the key value for determination at a single time-point. 13C-phenylalanine breath test is safe and helpful in distinguishing different stages of hepatic dysfunction for elderly cirrhosis patients.