Continuous 13C-methacetin breath test differentiates biliary atresia from other causes of neonatal cholestasis.
OBJECTIVE
Distinguishing biliary atresia (BA) from other causes of neonatal cholestasis (NC) is challenging. Continuous BreathID C-methacetin breath test (MBT) is a novel method that determines liver function. Methacetin is metabolized uniquely by the liver and CO2 is measured passively, through a nasal cannula in the exhaled breath. The aim of this study was to assess the ability of MBT to differentiate BA from other causes of NC.


METHODS
MBT was performed in infants with NC before any invasive procedure. Percent dose recovered (PDR) peak and time to peak (TTPP) of C recovered were correlated with blood test results and degree of fibrosis on liver biopsy.


RESULTS
Fifteen infants were enrolled in the study. Eight were eventually diagnosed as having BA. MBT showed that infants with NC from various causes reached the PDR peak after 44.5 ± 6.7 minutes, whereas infants with BA reached the PDR peak value after 54.7 ± 4.3 minutes (P < 0.005). This suggested low cytochrome P450 1A2 activity in the BA group. The area under the curve (AUC) was 0.95 (95% confidence interval [CI] 0.83-1), sensitivity of 88%, and specificity of 100%.


CONCLUSIONS
This pilot study shows that MBT can differentiate between BA and other causes of NC by time to peak of methacetin metabolism. The results suggest that MBT may be used as part of the diagnostic algorithm in infants with liver disease. Larger-scale studies should be conducted to confirm these initial observations.
Pediatric Gastroenterology Unit, Department of Pediatrics, Hadassah-Hebrew University Medical Center, Jerusalem, Israel. eyals@hadassah.org.il
Eyal
E
Shteyer
Gadi
G
Lalazar
Nilla
N
Hemed
Orit
O
Pappo
Esther
E
Granot
Baruch
B
Yerushalmi
Eitan
E
Gross
D000081:Acetamides / Q000378:metabolism; D019540:Area Under Curve; D001652:Bile Ducts; D001656:Biliary Atresia / Q000150:complications / Q000175:diagnosis* / Q000378:metabolism; D001944:Breath Tests / Q000379:methods; D002245:Carbon Dioxide / Q000378:metabolism*; D002247:Carbon Isotopes; D002779:Cholestasis / Q000175:diagnosis* / Q000378:metabolism; D016001:Confidence Intervals; D019388:Cytochrome P-450 CYP1A2 / Q000378:metabolism; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007223:Infant; D008099:Liver / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D008105:Liver Cirrhosis, Biliary / Q000175:diagnosis* / Q000209:etiology / Q000378:metabolism; D008111:Liver Function Tests; D008297:Male; D012680:Sensitivity and Specificity
D000081:Acetamides; D002247:Carbon Isotopes; C035495:methacetin; D002245:Carbon Dioxide; D019388:Cytochrome P-450 CYP1A2