Childhood Diseases

Updated 11 March 2016

Diagnosing chickenpox

It is easy to identify the rash of blisters of chickenpox, so laboratory test are not necessary.


Chickenpox is usually an easily recognisable disease because of the distinctive rash of blisters. For this reason, laboratory tests are not often necessary.

If there is doubt, the virology laboratory can do rapid tests on fluid obtained from a vesicle with a tiny needle and syringe or on cellular material obtained by swabbing the raw base of a vesicle.

In situations of exposure to chickenpox, the knowledge that a person has definitely had chickenpox before is useful when deciding what measures, if any, need to be taken.

Often this information is not known or is incorrect, such as when adults try to recall whether they had chickenpox as a child.

In circumstances where an at-risk person has been exposed to chickenpox, a blood test can be done to show whether they have antibodies to the varicella-zoster virus.

The presence of antibodies means that they had had chickenpox in the past and that they are therefore wholly or only partially protected as with immune compromised people.

Read more: 

Risk factors for chickenpox 

Treating chickenpox       

Causes of chickenpox

Revised and reviewed by Prof Eugene Weinberg, paediatrician and Paediatric Allergist, Health24 expert, February 2015.


Ask the Expert


Prof Eugene Weinberg worked in the Paediatrics Department of the Red Cross Children’s Hospital for many years. He is presently a paediatric allergist at the Allergy Diagnostic Unit of the UCT Lung Institute in Mowbray.

Still have a question?

Get free advice from our panel of experts

The information provided does not constitute a diagnosis of your condition. You should consult a medical practitioner or other appropriate health care professional for a physical exmanication, diagnosis and formal advice. Health24 and the expert accept no responsibility or liability for any damage or personal harm you may suffer resulting from making use of this content.

* You must accept our condition

Forum Rules