(13)CO(2) breath tests: comparison of isotope ratio mass spectrometry and non-dispersive infrared spectrometry results.
OBJECTIVE
Isotope ratio mass spectrometry is the standard analytical method for (13)CO(2) breath tests. The goal of this study was to compare the results of (13)CO(2) breath tests obtained by non dispersive infrared spectrometry, a new, simpler and cheaper method, with those obtained by the gold standard method.


METHODS
Three hundred and eight patients were included: 150 underwent a urea breath test for Helicobacter pylori diagnosis, 140 an aminopyrine breath test to measure liver function, and 18 an octanoic acid breath test for gastric emptying evaluation. A total of 750 breath samples were obtained in duplicate for isotope ratio mass and infrared spectrometry analyses. Breath test results were compared using Bland-Altman plots.


RESULTS
The agreement between the two methods was excellent for urea breath tests (kappa coefficient=0.96), with only 3 discordant results. Although (13)C isotopic enrichment in breath was significantly lower with infrared spectrometry (P<0.0001), the agreement for the results of aminopyrine and octanoic acid breath tests was excellent. The clinical significance of these tests was similar for both methods.


CONCLUSIONS
Infrared spectrometry results are comparable to isotope ratio mass spectrometry. Because this analytical method is simpler and less expensive, it could be used for clinical applications of (13)CO(2) breath tests.
Mion
F
F
Fédération des Spécialités Digestives, Hôpital Edouard-Herriot, Lyon, France. francois.mion@chu-lyon.fr
Ecochard
R
R
Guitton
J
J
Ponchon
T
T
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000632:Aminopyrine / Q000032:analysis; D001944:Breath Tests; D002210:Caprylates / Q000032:analysis; D002247:Carbon Isotopes; D005260:Female; D005746:Gastric Emptying; D016481:Helicobacter Infections / Q000175:diagnosis; D016480:Helicobacter pylori; D006801:Humans; D016014:Linear Models; D008111:Liver Function Tests; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D013055:Spectrophotometry, Infrared; D014508:Urea / Q000032:analysis
D002210:Caprylates; D002247:Carbon Isotopes; D000632:Aminopyrine; D014508:Urea; C031492:octanoic acid