Laboratory confirmation of varicella zoster virus is not normally required, because varicella diagnosis is most commonly made by clinical assessment. Laboratory testing has been recommended to confirm the diagnosis of severe or unusual cases or to determine susceptibility to varicella. However, as varicella incidence continues to decline, the likelihood of clinical misdiagnosis increases. Varicella in vaccinated persons is usually mild or atypical and can pose particular challenges for clinical diagnosis. Therefore, laboratory confirmation of varicella cases is becoming more important, as fewer cases are seen and a higher proportion of these few are vaccinated.

Instructions for collecting specimens
Below is to a video developed for health care professionals to illustrate the most appropriate procedures for collecting varicella zoster virus (VZV) skin lesions and blood specimens. Also, be sure to download the specimen collection form which should be sent along with the specimen to the CDC.

Length of video is 4 minutes.

Links to download video file	File*	Size
Video file (compressed for quick download)	video	2 MB
Video file (higher quality, non-compressed for BroadBand or local computer use)	video	14 MB
Video file (highest quality, non-compressed for those connecting via DSL or accessing via a local area network)	video	16 MB
Link to download collection form	Printable	Accessible
Specimen collection form	.pdf version	text-only**

* Windows Media Player can be used to view these files. If you do not have Windows Media Player, it can be obtained as a free download from the Microsoft website at http://www.microsoft.com/windows/windowsmedia/players.aspx

** The text version is provided for those that require text-only documents for screen-reader devices. Please contact NIPINFO@cdc.gov via email, if you need further any assistance.

Script of Video

This video outlines procedures for collecting varicella skin lesions and blood specimens. Skin lesions are the preferable method for laboratory confirmation of varicella. Blood specimens should be used to test for varicella immunity.

There are 3 types of lesions you will see most often resulting from varicella zoster virus, a scabbed or crusted lesion; a maculo-papular lesion, which is a lesion with a raised red bump; or a vesicular lesion, which is a blister-like or fluid filled lesion.

To collect a scab for varicella zoster virus testing, begin by gently lifting the scab from the lesion. Once the scab is collected, place it in a container such as a swab specimen tube or a plastic baggie. If there is more than one scab, place each scab individually in different containers.

The most effective technique for collecting cells from a maculopapular lesion or fluid from a vesicular lesion is the same, though for maculopapular lesions it is a greater challenge to ensure that enough skin cells are collected. Lesions in vaccinated individuals are likely to be atypical, macular only or papular only, but obtaining specimens from papular lesions is possible using the following technique. Use the edge of a clean slide to loosen and collect skin cells or fluid from the lesion as shown here. Then, using a sterile swab, rub the lesion vigorously enough to ensure that skin cells or fluid are collected. To ensure an adequate amount of skin cells is collected, particularly with maculopapular lesions, we recommend also using the swab to wipe the skin cells off the edge of the slide used to scrape the lesion. You may also press the slide directly to the lesion to collect skin cells or fluid as shown here. This technique is especially effective for vesicles where a “smudge” should be visible. To ensure that skin cells or fluid are on the slide, compare it to a clear slide under light, as shown here.**

To collect a blood specimen for varicella immunity testing perform a finger stick on the individual. Soak the circle on the filter paper with blood ensuring that the circle is completely full and check to see that blood has soaked through to the other side. Then soak the remaining circle, and again ensure that blood has soaked through both sides of the filter paper. Allow the blood to dry before packaging the filter paper. Venupuncture is also an acceptable method for blood collection. Collect at least 1 ml of blood into a serum-seperator vaccutainer tube. Before storage or shipping, separate the serum from the cells in a centrifuge for 15 minutes.

For more information on varicella zoster virus specimen collection, storage, and handling, please contact:

Centers for Disease Control and Prevention
National VZV Laboratory
1600 Clifton Road, NE
Mailstop G-18
Atlanta, GA 30333
Phone: (404) 639-3667
Fax: 404-639-4056
Email: vzvlab@cdc.gov

This page last modified on January 14, 2005