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.
Oztürk
Emel
E
Department of Nuclear Medicine, Gülhane Military Medical Academy and Medical School, 06018, Etlik, Ankara, Turkey. docemelozturk@hotmail.com
Yeşilova
Zeki
Z
Ilgan
Seyfettin
S
Arslan
Nuri
N
Erdil
Ahmet
A
Celasun
Bülent
B
Ozgüven
Mehmet
M
Dağalp
Kemal
K
Ovali
Onder
O
Bayhan
Hikmet
H
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