Syphilis

Dark-field microscopy - step 1

Direct detection of T. pallidum by dark-field microscopy is useful when a lesion is present. Dark-field microscopic examination of fluid from the chancre offers the most definitive diagnosis. If no fluid is present, the lesion can be abraded, then a small amount of normal saline added to create a specimen - as seen in this and the following slides.

If smears cannot be examined immediately or if the lesion is oral, then direct fluorescent antibody testing (with similar specimen collection methods) is a practical alternative.

It is extremely important to contact the laboratory in your region for specific instructions on collecting and preparing specimens.

Here, the lesion is cleansed with normal saline in preparation for collecting a specimen for laboratory diagnosis of suspected syphilis.

Source: Boehringer-Ingelheim