A VEB investigator who is a Staff Member at the NIH Clinical Center, interviews each subject, performs a physical examination, draws a blood sample, and, when appropriate for the disease or virus under study, obtains other clinically indicated biological specimens, such as urine, sputum, saliva, tears, semen, Pap smear, or cervical, anal, oral, or nasal swabs. On occasion, other relatively non-invasive studies may be indicated. Skin testing with conventional, licensed antigens for assessment of cellular immunity may be performed, and skin lesions may be biopsied or excised. Tumor or other tissue biopsies may be obtained when biopsy or surgery is clinically indicated for other reasons. Otherwise no surgery is performed, and no therapy is administered. Clinical referral to other components of NCI, NIH, or the private sector are made as needed. The biological specimens are frozen or otherwise preserved to be batch tested in current assays or future assays that will be developed. Such laboratory testing is performed either at VEB's own support laboratory, or collaboratively in other NCI, NIH, or extramural laboratories that have the needed expertise for the disease or virus under study.