Special Precautions/Comments:

N.B. Please supply details of vaccination history (if known) with all requests in addition to any relevant clinical details.

This test is suitable for the assessment of diphtheria immune status, it is not suitable for the diagnosis of active disease (please refer to Diphtheria Culture).

Method: Diphtheria immunity status is determined by a tissue culture toxin neutralisation assay of serum antibodies specific for diphtheria toxin. Test plates are incubated for up to 6 days before a final report is issued.  Calibration: – EQA scheme: – IQC: –

Interpretation: Results are reported in International Units/mL and classified as:
• individual is susceptible: <0.016 IU/mL
• levels conferring some protection: 0.016 to 0.09 IU/mL
• protective levels: 0.1 to 0.9 IU/mL
• levels conferring long-term protection: >1 IU/mL

For further information contact UKHSA Colindale, Respiratory and Vaccine Preventable Bacteria Reference Unit (RVPBRU).

Additional Information:

Background information: Diphtheria is an acute infectious disease of the upper respiratory tract and occasionally the skin. It is caused by toxigenic strains of Corynebacterium diphtheriae, of which there are 4 biotypes, (gravis, mitis, intermedius and belfanti), Corynebacterium ulcerans and Corynebacterium pseudotuberculosis.

All can carry the phage-borne diphtheria toxin gene. In a fully developed case of diphtheria, this toxin damages the pharyngeal epithelium to produce a leathery membrane, giving the disease its name. This membrane may occlude the airway, sometimes causing death by respiratory obstruction. Systemic absorption of the toxin may also cause damage to the heart and nervous system, causing or contributing to disability or death.

The usual site of carriage or infection is the throat or nasopharynx, occasionally the nose.

Keywords: Diphtheria, throat, pharyngitis, tonsillitis, travel abroad, animal contact, unpasteurised milk unpasteurised dairy