Diagnosis

Diagnosis of parvovirus B19 infection is done by measuring (1)

• specific IgM and IgG antibodies to parvovirus B19
• IgM is useful in diagnosing acute infection in immuncompetent patients
• sensitivity is 89% and specificity is 99% (2)
• IgM is seen 10–12 days after infection and usually persists for another 3-4 months (occasionally for a longer period) (1)
• presence of IgG without IgM indicates previous infection of more than two months (3)
• in the absence of both IgG and IgM, a second serum test should be done one month after the contact date or after symptoms appear
  • if IgM is detected a further test should be done within 7 to 10 days and if felt appropriate refer the patient to a reference laboratory for confirmation of the test (3)
• B19 DNA in blood or tissue samples through PCR (1)
  • B19 DNA can be detected in serum, bone marrow and other tissues for diagnostic purposes (1)
  • important in diagnosing parvovirus infection in patients with transient aplastic crisis or in immunocompromised patients with chronic infection (2)
• infection with erythrovirus (parvovirus) B19 may result in a false positive Paul Bunnell test

Reference:

• (1) Broliden K, Tolfvenstam T, Norbeck O. Clinical aspects of parvovirus B19 infection. J Intern Med. 2006;260(4):285-304
• (2) Servey JT, Reamy BV, Hodge J. Clinical presentations of parvovirus B19 infection. Am Fam Physician. 2007;75(3):373-6
• (3) Health Protection Agency (HPA) 2007. Investigation of red rash. QSOP 56. Issued by standards unit, evaluations and standards laboratory. Centre for infections