13C-methacetin breath test as liver function test in patients with chronic hepatitis C virus infection.
BACKGROUND
The 13C-methacetin breath test enables the quantitative evaluation of the cytochrome P450-dependent liver function.


OBJECTIVE
To find out whether this breath test is sensitive in noncirrhotic patients also with chronic hepatitis C in early stages of fibrosis.


METHODS
Sixty-one healthy controls and 81 patients with chronic hepatitis C underwent a 13C-methacetin breath test. In all patients, a liver biopsy was performed. The liver histology was classified according to the histology activity index-Knodell score.


RESULTS
Delta over baseline values of the patients at 15 min significantly differed from controls (19.2 +/- 9.2 per thousand vs. 24.1 +/- 5.7 per thousand; P < 0.003). The cumulative recovery after 30 min in patients was 11.4 +/- 4.8% and in healthy controls 13.8 +/- 2.8% (P < 0.002). However, patients with early fibrosis (histology activity index IVB) did not differ in delta over baseline values of the patients at 15 min (23.2 +/- 7.9 per thousand vs. 22.6 +/- 7.2 per thousand; P = 0.61) or cumulative recovery (13.6 +/- 3.7% vs. 13.2 +/- 3.8%; P = 0.45) from patients with more advanced fibrosis (histology activity index IVC). Patients with clinically nonsymptomatic cirrhosis (histology activity index IVD; Child A) metabolized 13C-methacetin to a significantly lesser extent (delta over baseline values of the patients at 15 min: 8.3 +/- 4.9 per thousand; P < 0.005 and cumulative recovery after 30 min: 5.6 +/- 3.2%; P < 0.003). The 13C-methacetin breath test identified cirrhotic patients with 95.0% sensitivity and 96.7% specificity.


CONCLUSIONS
The non-invasive 13C-methacetin breath test reliably distinguishes between early cirrhotic (Child A) and noncirrhotic patients, but fails to detect early stages of fibrosis in patients with chronic hepatitis C.
Braden
B
B
Medical Department II, University Hospital, Frankfurt/Main, Germany. braden@em.uni-frankfurt.de
Faust
D
D
Sarrazin
U
U
Zeuzem
S
S
Dietrich
C F
CF
Caspary
W F
WF
Sarrazin
C
C
D000081:Acetamides; D000328:Adult; D000368:Aged; D001944:Breath Tests / Q000379:methods; D002250:Carbon Radioisotopes; D016022:Case-Control Studies; D005260:Female; D019698:Hepatitis C, Chronic / Q000150:complications* / Q000503:physiopathology; D006801:Humans; D008103:Liver Cirrhosis / Q000150:complications / Q000175:diagnosis*; D008111:Liver Function Tests / Q000592:standards; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D017211:Treatment Failure
D000081:Acetamides; D002250:Carbon Radioisotopes; C035495:methacetin