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Unit Code 800112:
Helicobacter pylori Antibody, IgA, Serum

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Useful For

 Screening for Helicobacter pylori infection

Clinical Information

 Helicobacter pylori is a spiral-shaped, gram-negative bacillus

that has been associated with gastritis, gastric and duodenal

ulcers, and gastric malignancies.

 

Helicobacter pylori is found worldwide. In Caucasian populations

in the United States and other industrialized countries,

Helicobacter pylori infection is infrequent in childhood. Prevalence

increases 0.5-2% with each year of age, reaching about 50% in

those who are 60 or older. Prevalence rates appear to be higher

in blacks and Hispanics than in whites. In a random population of

200 apparently healthy blood donors tested for Helicobacter

pylori IgG antibody, the positive rate was 27.5% with an equivocal

rate of 5.5%.

 

The diagnosis of Helicobacter pylori gastrointestinal disease is

supported by the presence of serum antibodies: IgG, IgM, or IgA,

to the organism. Screening patients for the presence of antibodies

to Helicobacter pylori is a convenient, noninvasive means for

assessing whether gastrointestinal symptoms may be related to

Helicobacter pylori infection.

 

Because serology may lack specificity, additional noninvasive

tests can be used to confirm Helicobacter pylori infection

including the urease breath test (#81590 "Helicobacter pylori

Breath Test") or stool antigen test for Helicobacter pylori (#81806

"Helicobacter Pylori  Antigen, Feces"). The gold standard for

diagnosis of Helicobacter pylori disease is a biopsy of infected

tissue and evaluating the tissue by Gram, silver, Giemsa, or

acridine orange stains; or by immunofluorescence or immuno-

peroxidase methods; rapid urease testing; and/or culture.

Reference Values

< or = 12.50 U/mL (negative)

12.51-19.99 U/mL (equivocal)

> or =20.00 U/mL (positive)

Interpretation

Patients with Helicobacter pylori infection nearly always develop

antibodies of the IgG class and less frequently develop antibodies

of the IgA class. IgM antibodies may be produced shortly after

the onset of infection. Levels of IgM antibodies should decrease

after successful treatment, but may again increase if recurrence

or relapse of infection occurs.

Cautions

This assay should be performed only on patients with gastro-

intestinal symptoms because of the large percentage of

Helicobacter pylori-colonized individuals, especially in older age

groups (estimated to be 40-60% of asymptomatic Caucasians

older than 60 years).

 

The serologic results must be interpreted in light of the clinical

signs and symptoms of the patient.

Clinical Reference

 1.  Blaser MJ:  Helicobacter pylori and related organisms. In

      Principles and Practice of Infectious Diseases. Vol. 2. 4th

      edition. Edited by GL Mandell, R Dolin, JE Bennett. Churchill

      Livingstone Inc., 1995, pp 156-164

 

2.   Perez-Perez GI, Taylor DN, Bodhidatta L, et al: 

      Seroprevalence of Helicobacter pylori infections in Thailand.

      J Infect Dis 1990;29:2139-2143

 

3.   Drumm B, Perez-Perez GI, Blaser MJ, et al:  Intrafamilial

      clustering of Helicobacter pylori infection. N Engl J Med 1990;

      322:359-363

 

4.   Morris AJ, Ali MR, Nicholson GI, et al:  Long term follow-up of

      voluntary ingestion of Helicobacter pylori. Ann Intern Med

      1991;114:662-663

 

5.   Evans DJ Jr, Evans DG, Graham DY, et al:  A sensitive and

      specific serologic test for detection of Campylobacter pylori

      infection. Gastroenterology 1989;96:1004-1008

 

6.   Glassman MS, Dallal S, Berezin SH, et al:  Helicobacter pylori

      related gastroduodenal disease in children. Diagnostic utility

      of enzyme-linked immunosorbent assay (ELISA). Dig Dis Sci

      1990;35:993-997

Key