Finally, one should keep in mind that the positive predictive value of a serologic test used in screening in low-prevalence populations is low.

In fact, palmar lesions are sufficiently characteristic as to almost always warrant a serologic test for syphilis regardless of the remainder of the clinical picture.

The Food and Drug Administration mandates certain screening tests for blood--including tests for Hepatitis B surface antigen (HBsAg), Hepatitis B core antibody (anti-HBc), Hepatitis C Virus (HCV) antibody (anti-HCV), Human Immunodeficiency Virus (HIV) types 1 and 2 (anti-HIV-1 and anti-HIV-2), Human T-Lymphotropic Virus (HTLV) types I and II (anti-HTLV-I and anti-HTLV-II), serologic test for syphilis, Nucleic Acid Amplification Testing (NAT) for HIV-1 and HCV, and NAT for West Nile Virus.