A short presentation for the different laboratory techniques used in diagnosing Helicobacter Pylori infection. A special focus is given for the diagnostic performance of every test.

1. Laboratory Diagnosis of
H. Pylori Infection
Ola H. Elgaddar
MD, PhD, CPHQ, LSSGB
Lecturer of Chemical Pathology
Alexandria University
Ola.elgaddar@alexu.edu.eg

2. Prevalence of H. pylori infection
The Helicobacter Foundation, 2014

3.  Gram –ve Bacteria
 Colonizes 50% of the
world population
 Virulent strains may
cause gastritis, ulcers,
adenocarcinoma & gastric
mucosa-associated
lymphoid tissue (MALT)
lymphoma
 Class I carcinogen
(WHO).
Formichella et al. Clin Vaccine Immunol 2013; 20: 1703-10

4. Diagnosis of H. Pylori
INVASIVE NON
INVASIVE
 Histopathology
 Rapid Urease Test
 Culture
 PCR
 Urea Breath Test
 Stool Ag
 Serology

5. Diagnostic Performance
Denise et. al. Nature Reviews Nephrology 2014; 10: 215–25.

6. Non – Invasive Tests
1) Urea (14C) Breath Test

7. Non – Invasive Tests
1) Urea (14C) Breath Test
 95% Sensitivity, 100% Specificity,
100% PPV, 96 % NPV
 Ideal for monitoring therapeutic outcomes
 Patients not on PPI for 1 week
Petrovic et.al. Hell J Nucl Med 2011; 14: 21–4.

8. Non – Invasive Tests
2) Stool Monoclonal Ag
 Performance differs
according to reagents
 88% Sensitivity, 98% Specificity,
88% PPV, 98 % NPV
 FDA approved for therapeutic monitoring
 Confirm eradication after 4-8W. of Rx
 Not affected by PPIs

9. Non – Invasive Tests
3) Serology (IgG / AgA)
 Either Abs against
whole bacterial cell or
against specific proteins
 Good negative test
 Not all H. pylori-infected subjects develop
disease.
 It depends on the strain heterogeneity
based on the expression of certain
virulence factors,

11. Non – Invasive Tests
3) Serology
 Six highly immunogenic virulence factors,
CagA (Cytotoxin-associated-gene A),
VacA (Vacuolating Cytotoxin A), GroEL,
gGT, HcpC, and UreA, are currently being
detected.
 Most of them are present in all strains but
expressed only in certain ones.
 97.6% Sensitivity and 96.2% Specificity;
much higher than whole cell Abs

12. Invasive Tests
Kanna et. al. Gastroenterology and Endoscopy news 2013 (e-published)

13. THANK
YOU