Reasons, Procedure and Preparation For EIA Blood Test

Submitted on March 27, 2012

What is a EIA Test?

The enzyme immunosorbant assay (EIA) test is a series of blood tests which are done to diagnose infection with the human immunodeficiency virus (HIV). This test is also referred to as the ELISA test. It is often done in conjunction with the Western Blot test to confirm the presence of HIV in the blood.


In EIA testing, blood needs to be drawn from a vein. This is usually done from the back of the hand or the inside of the elbow.

The site from where blood will be drawn is cleaned with an antiseptic, an elastic band is wrapped around the upper arm (to make the vein swell and to apply pressure). A needle is now inserted and the blood is collected, usually in an airtight capsule or vial which has been attached to the needle. After the blood has been collected, the puncture site is covered with a bandage to keep infections at bay.

In young children or babies, a lancet (a sharp tool) is usually used to puncture the skin. The blood is collected onto a test strip or slide, or in a pipette (a small glass tube). The area may then be lightly bandaged.


No preparation may be necessary. Your healthcare provider may however ask you to stop any medication or drugs which may affect the result of the test. You may also be asked to stop any medication, which may contain blood thinners.

Will it hurt and is there any risk? There is only a mild pain, or a stinging or pricking sensation as the needle is inserted.

There is usually no risk involved, but depending upon your pain threshold, you may feel light-headed or faint. Sometime there is a hematoma (accumulation of blood) at the site of the puncture. An infection may occur if the site is not kept clean.

Reasons for EIA Blood Test

It is advisable to go for an EIA test if you have had unprotected sex with:

  • Someone who has AIDS or HIV.
  • Someone who has had multiple partners.
  • A commercial sex worker.
  • Someone who shares needles or uses injectible drugs.
  • If you are not sure whether your partner was infected with HIV.
  • If you have any sexually transmitted disease like syphilis or genital herpes.

Further Tests Required

Further tests like the VDRL or RPR are required to confirm the results.