Alternative name
(Also known as functional antibodies)
Description
The terms “Functional or Specific antibodies” refer to tests for the measurement of IgG antibody levels to Tetanus/Haemophilus influenzae b and Pneumococcal polysaccharide used in order to define the efficiency of the antibody response in immunocompromised individuals. Measurement of specific antibody production (spontaneous and post immunisation) is useful in the assessment of patients with suspected immune (immunoglobulin) deficiency (hereditary or acquired).
The pneumococcal antibody test is of limited use in testing for specific immunisation status since the new vaccines contain very different serotypes.
Indication
Investigating humoral immune deficiency associated with (SPUR) severe, protracted, recurrent unusual or recurrent infection – particularly URTI, LRTI. Also, response to vaccination in immuno- compromised e.g. splenectomy, patients. A widely misused test – not to be used as general test of vaccination and certainly not as a test of infection.
Interpretation
Tetanus toxoid – a test of immunolgical memory upon vaccination.
Pneumococcal polysaccharide (Pneumovax) – a test of responses to polyscacharide antigens.
Haemnophilusb (protein polysaccharide) – used as a test of response to protein vaccine. Vaccination history must be known.
- If responses are poor repeat vaccination and reevaluate.
- Never use live vaccines suspect patients.
Sample
Serum Separator Tube (SST)
Assay details
ELISA
Restrictions
Referred test
Reference range
Haemophilus b: <0.1ug/ml
Pneumococcal polysaccharide (Pneumovax): <10ug/ml
Tetanus toxoid: <0.01ug/ml
Assay range notes
Equivocal
Hib: 0.1-1.0ug/ml
PCP: 10-30ug/ml
Tet: 0.01-0.15ug/ml
Positive
Hib: > 1.0ug/mlPCP: > 30ug/mlTet: > 0.15ug/ml
Turnaround time
28 day
Analysing laboratory
North Cumbria