Hemagglutination Inhibition (HAI) Assay
<<Return to LaboratoryRequisition Forms
Reference Details
Serological detection of total antibodies (IgM and IgG) directed towards Western equine encephalitis (WEE) virus by Hemagglutination Inhibition (HAI) assay.
- Western Equine Encephalitis
Sérum. Volume minimum requis: 400 mL. Un échantillon de liquide céphalorachidien (LCR) peut être soumis (200 mL) dans les cas d’infection du système nerveux central pour démontrer que le virus a traversé la barrière hémato-encéphalique. Cependant, le LCR ne sera analysé que lorsque la présence d’anticorps anti-WEE dans le sérum du patient aura été démontrée (par IHA).
Collect blood in serum separator tubes.
Shipping of specimens shall be done by a TDG certified individual in accordance with TDG regulations. For additional information regarding classification of specimens for the purposes of shipping, consult either Part 2 Appendix 3 of the TDG Regulations or section 3.6.2 of the IATA Dangerous Goods Regulations as applicable.
Given the rarity of WEEV in Canada and elsewhere in North America, diagnostic testing will only be considered when clinical suspicion of WEEV infection is very strong and fit with the seasonality for this arbovirus. Consultation with NML laboratory personnel is strongly encouraged prior to sample submission.
Completed Viral Zoonoses requisition including sender laboratory name, address and telephone number. Patient name and / or identifier (specimen reference number), date of birth, test(s) requested, collection date of specimen, date of on-set of symptoms, and clinical and travel history of patient.
To demonstrate seroconversion, both acute and convalescent samples must be tested in parallel.
The HAI assay is used to measure the level of antibodies in a patient’s serum that will prevent the agglutination of susceptible erythrocytes by inactivated antigens that are able to attach to the erythrocyte receptors on red blood cells. A fourfold or greater increase or decrease in titre between the acute phase and convalescent phase serum is considered to be diagnostic of infection with western equine encephalitis virus. Results are expressed as the reciprocal of antibody titre.
14 Calendar days.
- Clarke, D.H. and Casals, J. Techniques for hemagglutination and hemagglutination-inhibitiion with arthropod-borne viruses. Am. J. Trop. Med. And Hyg. 1958; 7: 561-573.