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

Specimen Required

Supplies: Sarstedt 5 mL Aliquot Tube (T914) 

Collection Container/Tube:

Preferred: Serum gel 

Acceptable: Red top 

Submission Container/Tube: Plastic vial 

Specimen Volume: 0.5 mL 

Collection Instructions: Centrifuge and aliquot serum into a plastic vial. 


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

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Heat-inactivated Reject

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.


This assay does not provide diagnostic proof of the presence or absence of immune deficiency. Results must be confirmed by clinical findings and other laboratory tests.

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

Method Description

Microwells are precoated with the Haemophilus influenzae type B (HIB) capsular polysaccharide antigen conjugated to human serum albumin. The calibrators, controls, and diluted patient specimens are added to the wells and antibodies recognizing the HIB antigen bind during the first incubation. After washing the wells to remove all unbound proteins, purified peroxidase-labeled rabbit antihuman IgG (gamma chain specific) conjugate is added. The conjugate binds to the captured human antibody and the excess unbound conjugate is removed by a further wash step. The bound conjugate is visualized with 3,3',5,5' tetramethylbenzidine (TMB) substrate, which gives a blue reaction product, the intensity of which is proportional to the concentration of antibody in the specimen. Phosphoric acid is added to each well to stop the reaction. This produces a yellow end point color, which is read at 450 nm.(Madore DV, Anderson P, Baxter BD, et al: Interlaboratory study evaluating quantitation of antibodies to Haemophilus influenzae type B polysaccharide by enzyme-linked immunosorbent assay. Clin Diagn Lab Immunol. 1996;3[1]:84-88. doi: 10.1128/cdli.3.1.84-88.1996.; Bennett JE, Dolin R, Blaser MJ, eds: Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020)

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