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Test ID HIBSG Haemophilus influenzae Type B Antibody, IgG, Serum

Specimen Required

Supplies: Sarstedt 5 mL Aliquot Tube (T914)


Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL


If not ordering electronically, complete, print, and send Infectious Disease Serology Test Request (T916) with the specimen.

Useful For

Assessing a patient's immunological (IgG) response to Haemophilus influenzae type B (HIB) vaccine


Assessing immunity against HIB


Aiding in the evaluation of immunodeficiency when the patient is tested pre- and post-vaccination

Method Name

Enzyme Immunoassay (EIA)

Reporting Name

Haemophilus influenzae B Ab, IgG, S

Specimen Type


Specimen Minimum Volume

0.4 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 7 days
  Frozen  7 days

Clinical Information

Haemophilus influenzae type B (HIB) is an encapsulated Gram-negative cocco-bacillary bacterium that can cause devastating disease in unvaccinated young children, including meningitis, bacteremia, cellulitis, epiglottitis, pneumonia, and septic arthritis. The outer surface of H influenzae is covered by a polyribosyl-ribitol-phosphate (PRP) polysaccharide that is responsible for both pathogenicity and immunity. There are currently 6 recognized PRP serotypes, referred to as a through f, among which serotype b, prior to the availability of a vaccine, accounted for up to 95% of infections. There are also unencapsulated or nontypable strains.


Prior infection with H influenzae is associated with protective immunity against reinfection. One of the great advances in modern medicine has been the development of an effective vaccine against HIB, which is based on use of an unconjugated, purified PRP antigen. A patient's immunological response to HIB vaccine can be determined by measuring anti-HIB IgG antibody levels using a standardized enzyme immunoassay (EIA). Antibody levels of1 mcg/mL or more at least 3 weeks after vaccination has been correlated with long-term protective immunity.

Reference Values

≥0.15 mg/L

Reference values apply to all ages.


An anti-Haemophilus influenzae type B (HIB) IgG antibody concentration of 0.15 mcg/L is generally accepted as the minimum level for protection at a given time; however, it does not confer long-term protection. A study from Finland suggested that the optimum protective level is 1.0 mcg/L postimmunization.(1) Furthermore, studies have shown that the response to HIB vaccine is age-related.

Clinical Reference

1. Peltola H, Kayhty H, Virtanen M, Makela PH l: Prevention of Haemophilus influenzae type B bacteremic infections with the capsular polysaccharide vaccine. N Engl J Med. 1984;310(24):1561-1566. doi: 10.1056/NEJM198406143102404

2. Berger M: Immunoglobulin G subclass determination in diagnosis and management of antibody deficiency syndromes. J Pediatr. 1987;110(2):325-328. doi: 10.1016/s0022-3476(87)80182-8. 

3. Murphy TF: Haemophilus species, including H influenzae and H ducreyi (Chancroid). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020:2743-2752

Day(s) Performed

Monday, Friday

Report Available

1 to 6 days

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
HIBSG Haemophilus influenzae B Ab, IgG, S 11257-3


Result ID Test Result Name Result LOINC Value
HIBSG Haemophilus influenzae B Ab, IgG, S 11257-3