Clotted Blood or Serum for Antibody Studies
Paired sera are usually required, one in the acute and the second in the convalescent phase (10-14 days after onset). We need to know enough clinical detail to decide which viruses to screen for, and a date of onset to decide whether waiting for a second serum is appropriate.
Only a limited range of viruses is tested for, and often serology is unhelpful, e.g. for coxsackie and echo viruses where culture or PCR of throat swab and faeces is suitable. Viral serology is helpful when a specific virus is suspected (e.g. rubella, CMV, mumps), or with particular problems such as rash, flu-like, and other respiratory tract infections. Patients with vague or long-standing problems (“lassitude” etc.) almost never produce diagnostic results. As a high proportion of people have antibody to Herpes simplex virus antibody tests are usually unhelpful: PCR is the diagnostic method of choice.