The CSD skin test was once used to to help diagnose cat scratch disease.

The test is virtually no longer used and not recommended. Today, better tests, such as the EIA test, are available to diagnose cat scratch disease.

The test site (an area with hair, usually the forearm) is cleansed. An antigen to cat scratch disease is injected just under the skin. After 48 - 72 hours, a health care provider will check the injection site to determine whether if your body has reacted to the substance.

There is no special preparation. People with dermatitis or other skin irritations should have the test performed on an area of skin where no irritation is present.

When the antigen is injected, you may feel a stinging sensation where the needle is inserted. After the reaction begins, the area may itch or burn.

This test was once used to diagnose cat scratch disease, before Bartonella henselae, the bacteria that causes CSD, was identified.

Inflammation around the injection site should be less than 5 millimeters wide.

An inflammation zone of greater than 5 millimeters may suggest that you have been infected with cat scratch disease recently or in the past.

• Allergic reaction, including itching and hives (rare)
• Possible spread of viruses to patient

Although this test has historical value, there are better tests available for the diagnosis of CSD. In addition, the CSD antigen is not widely available and carries the potential risk of transmitting other harmful substances such as viruses.