Helicobacter pylori infection diagnostic tests

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Yamuna Kondapally, M.B.B.S[2]

Overview

Endoscopic diagnostic tests are biopsy-based diagnostic methods for H. pylori infection. These include histology, rapid urease testing, culture and polymerase chain reaction (PCR).

Endoscopic Diagnostic Tests

  • In patients who have not been on a PPI within 1-2 wk or an antibiotic or bismuth within 4 wk of endoscopy, the rapid urease test (RUT) provides an accurate, inexpensive means of identifying H. pylori.
  • For patients who have been taking a PPI, antibiotics, or bismuth, endoscopic testing for H. pylori should include biopsies from the gastric body and antrum for histology with or without rapid urease testing.
  • Though culture or polymerase chain reaction (PCR) are the primary means by which antibiotic sensitivities can be determined, neither is widely available for clinical use in the United States and therefore, cannot be routinely recommended.

Endoscopic diagnostic tests are biopsy-based diagnostic methods for H. pylori infection. This include:

Histology

  • Site, number, and size of gastric biopsies
  • Method of staining
  • Level of experience of the examining pathologist
  • Advantage of histology over other diagnostic studies is its ability to detect the pathological changes associated with H. pylori infection such as inflammation, atrophy, intestinal metaplasia, and malignancy.[2]
  • Multiple biopsies are required for accurate diagnosis as the prevalence and density of H. pylori varies throughout the stomach. Therefore a minimum of three biopsies is taken from different sites. They are:[1][3]
  • Angularis
  • Greater curvature of the corpus
  • Greater curvature of the antrum

Rapid Urease Testing (RUT)

  • Identifies active H. pylori infection through the organism's urease activity.[5]
  • Procedure
  • The gastric biopsies obtained are placed into an agar gel or on a reaction strip containing urea, a buffer, and a pH-sensitive indicator.
  • The urea is metabolized to ammonia and bicarbonate in the presence of H. pylori's urease leading to a pH increase in the microenvironment of the organism.
  • A change in color of the pH sensitive indicator signifies the presence of the active infection.
  • The sensitivity of the RUT decreases due to medications such as bismuth-containing compounds, antibiotics, or PPIs which reduce the density and/or urease activity of H. pylori.[6]
  • It is recommended that biopsies are taken from two sites due to the patchy distribution of H. pylori infection after antibiotics use. The sites include:[7][4]
  • The body at the gastric angularis
  • Greater curvature of the antrum
  • PPIs are withheld for 1-2 wk before the performance of RUT as they reduce the sensitivity of the test.[8]

Culture

  • Culture is not as sensitive as RUT or histology.[9][10]
  • Highly specific method for identifying active H. pylori infection.
  • It is also used to determine antibiotic sensitivities and resistance.

Polymerase Chain Reaction (PCR)

  • PCR is highly specific and more sensitive than other biopsy-based diagnostic techniques.[11]
  • It is also used to identify mutations associated with antimicrobial resistance.[12][13][14][15]
  • This method is not standardized across laboratories
Endoscopic testing Advantages Disadvantages
*1. Histology
  • Excellent sensitivity (>95%) and specificity (95%)
  • Expensive and requires infrastructure and trained personnel
  • Detection improved by use of special stains- e.g. the Warhin-Starry silver stain, or the cheaper giemsa stain protocol
*2. Rapid urease testing
  • Inexpensive and provides rapid results.
  • Excellent specificity (98%) and very good sensitivity in properly selected patients.
  • Excellent specificity (99%)
  • Sensitivity significantly reduced in the post-treatment setting
*3. Culture
  • Excellent specificity.
  • Allows determination of antibiotic sensitivities
  • Expensive, difficult to perform and not widely available.
  • Poor sensitivity if adequate transport media are not available
  • Experience/ expertise required
*4. Polymerase chain reaction
  • Excellent sensitivity and specificity.
  • Allows determination of antibiotic sensitivities
  • Methodology not standardized across laboratories and not widely available
  • Considered experimental

References

  1. 1.0 1.1 el-Zimaity HM (2000). "Accurate diagnosis of Helicobacter pylori with biopsy". Gastroenterol Clin North Am. 29 (4): 863–9. PMID 11190070.
  2. Dixon MF, Genta RM, Yardley JH, Correa P (1996). "Classification and grading of gastritis. The updated Sydney System. International Workshop on the Histopathology of Gastritis, Houston 1994". Am J Surg Pathol. 20 (10): 1161–81. PMID 8827022.
  3. van IJzendoorn MC, Laheij RJ, de Boer WA, Jansen JB (2005). "The importance of corpus biopsies for the determination of Helicobacter pylori infection". Neth J Med. 63 (4): 141–5. PMID 15869042.
  4. 4.0 4.1 Woo JS, el-Zimaity HM, Genta RM, Yousfi MM, Graham DY (1996). "The best gastric site for obtaining a positive rapid ureas test". Helicobacter. 1 (4): 256–9. PMID 9398877.
  5. Uotani T, Graham DY (2015). "Diagnosis of Helicobacter pylori using the rapid urease test". Ann Transl Med. 3 (1): 9. doi:10.3978/j.issn.2305-5839.2014.12.04. PMC 4293486. PMID 25705641.
  6. Midolo P, Marshall BJ (2000). "Accurate diagnosis of Helicobacter pylori. Urease tests". Gastroenterol Clin North Am. 29 (4): 871–8. PMID 11190071.
  7. Chey WD, Woods M, Scheiman JM, Nostrant TT, DelValle J (1997). "Lansoprazole and ranitidine affect the accuracy of the 14C-urea breath test by a pH-dependent mechanism". Am J Gastroenterol. 92 (3): 446–50. PMID 9068466.
  8. Laine L, Estrada R, Trujillo M, Knigge K, Fennerty MB (1998). "Effect of proton-pump inhibitor therapy on diagnostic testing for Helicobacter pylori". Ann Intern Med. 129 (7): 547–50. PMID 9758575.
  9. Perez-Perez GI (2000). "Accurate diagnosis of Helicobacter pylori. Culture, including transport". Gastroenterol Clin North Am. 29 (4): 879–84. PMID 11190072.
  10. Lehours P, Ruskone-Fourmestraux A, Lavergne A, Cantet F, Mégraud F, Groupe d'Etude des Lymphomes Digestifs (GELD) for the Fédération Française de Cancérologie Digestive (FFCD) (2003). "Which test to use to detect Helicobacter pylori infection in patients with low-grade gastric mucosa-associated lymphoid tissue lymphoma?". Am J Gastroenterol. 98 (2): 291–5. doi:10.1111/j.1572-0241.2003.t01-1-07264.x. PMID 12591043.
  11. Zsikla V, Hailemariam S, Baumann M, Mund MT, Schaub N, Meier R; et al. (2006). "Increased rate of Helicobacter pylori infection detected by PCR in biopsies with chronic gastritis". Am J Surg Pathol. 30 (2): 242–8. PMID 16434900.
  12. Lawson AJ, Elviss NC, Owen RJ (2005). "Real-time PCR detection and frequency of 16S rDNA mutations associated with resistance and reduced susceptibility to tetracycline in Helicobacter pylori from England and Wales". J Antimicrob Chemother. 56 (2): 282–6. doi:10.1093/jac/dki199. PMID 15958499.
  13. Rimbara E, Noguchi N, Yamaguchi T, Narui K, Kawai T, Sasatsu M (2005). "Development of a highly sensitive method for detection of clarithromycin-resistant Helicobacter pylori from human feces". Curr Microbiol. 51 (1): 1–5. doi:10.1007/s00284-004-4488-z. PMID 15971095.
  14. de Francesco V, Margiotta M, Zullo A, Hassan C, Valle ND, Burattini O; et al. (2006). "Primary clarithromycin resistance in Italy assessed on Helicobacter pylori DNA sequences by TaqMan real-time polymerase chain reaction". Aliment Pharmacol Ther. 23 (3): 429–35. doi:10.1111/j.1365-2036.2006.02769.x. PMID 16423002.
  15. Ho GY, Windsor HM (2000). "Accurate diagnosis of Helicobacter pylori. Polymerase chain reaction tests". Gastroenterol Clin North Am. 29 (4): 903–15. PMID 11190075.

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