A new, practical, low-dose 14C-urea breath test for the diagnosis of Helicobacter pylori infection: clinical validation and comparison with the standard method.
The carbon-14 urea breath test (UBT) is a reliable and non-invasive technique for the diagnosis of Helicobacter pylori (HP) infection. In this study we evaluated the diagnostic performance of a new, practical and low-dose (14)C-UBT system for the diagnosis of HP and compared the results with those obtained using the standard method. Seventy-five patients (56 female, 19 male) with dyspepsia underwent (14)C-UBT and endoscopy with antral biopsies for histological analysis. The rapid urease test (CLO test) was applied to 50 of these patients. After a 6-h fasting period, a 37-kBq (14)C-urea capsule was swallowed for UBT. Breath samples were collected and counted using two different methods, the Heliprobe method and the standard method. In the Heliprobe method, patients exhaled into a special dry cartridge system (Heliprobe BreathCard) at 10 min. The activities of the cartridges were counted using a designated small GM counter system (Heliprobe analyser). Results were expressed both as counts per minute (HCPM) and as grade (0, not infected; 1, equivocal; 2, infected) according to the counts. In the standard method, breath samples were collected by trapping in a liquid CO(2) absorber. Radioactivity was counted as disintegrations per minute (SDPM) using a liquid scintillation counter after addition of a liquid scintillation cocktail. Histological examination was used as a gold standard. Two patients were excluded from the study because of inadequate biopsy sampling. Forty-eight patients (65%) were found to be HP positive on histology. The Heliprobe method correctly classified 48 of 48 HP-positive patients and 19 of 25 HP-negative patients (sensitivity 100%, specificity 76%, PPV 88%, NPV 100%, accuracy 91%). The standard method correctly classified 48 of 48 HP-positive patients and 20 of 25 HP-negative patients (sensitivity 100%, specificity 80%, PPV 90%, NPV 100%, accuracy 93%). On the other hand, the CLO test identified 26 of 32 HP-positive and 12 of 16 HP-negative patients (sensitivity 81%, specificity 75%, PPV 86%, NPV 66%, accuracy 79%). With the Heliprobe method, all of the positive results were grade 2, and all of the negative results were grade 0. No patients were defined as having grade 1 results. Counts allowed clear discrimination of HP-positive and -negative patients with both methods, the difference being statistically significant in each case ( P<0.001). A significant correlation was found between HCPM and SDPM ( r 0.863, P<0.001). According to the ROC analysis, the area under the curve was nearly the same with HCPM (AUC, 0.888; 95% CI, 0.785-0.992) and SDPM (AUC, 0.898; 95% CI, 0.802-0.994). In conclusion, the new (14)C-UBT system is a highly accurate method for the diagnosis of HP infection. It is rapid and practical, and therefore suitable for clinical and office practice.
Department of Nuclear Medicine, Gülhane Military Medical Academy and Medical School, 06018, Etlik, Ankara, Turkey. docemelozturk@hotmail.com
Emel
E
Oztürk
Zeki
Z
Yeşilova
Seyfettin
S
Ilgan
Nuri
N
Arslan
Ahmet
A
Erdil
Bülent
B
Celasun
Mehmet
M
Ozgüven
Kemal
K
Dağalp
Onder
O
Ovali
Hikmet
H
Bayhan
D000328:Adult; D001944:Breath Tests / Q000295:instrumentation* / Q000379:methods*; D002250:Carbon Radioisotopes; D004415:Dyspepsia / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000209:etiology; D005260:Female; D005756:Gastritis / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000382:microbiology*; D016481:Helicobacter Infections / Q000175:diagnosis / Q000000981:diagnostic imaging*; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014508:Urea
D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D014508:Urea