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Test ID: PARV    
Parvovirus B19 Antibodies, IgG and IgM, Serum

Useful For Suggests clinical disorders or settings where the test may be helpful

Diagnosing recent parvovirus infection (IgM)

 

Assessing past infection (eg, screening pregnant women) and immunity to parvovirus infection (IgG)

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Parvovirus B19 is the causative agent of fifth disease (erythema infectiosum, slapped cheek syndrome), which usually produces a mild illness characterized by an intensive erythematous maculopapular facial rash. Most outbreaks of parvovirus infection are acquired by direct contact with respiratory secretions and occur in the spring of the year. Close contact between individuals is responsible for infection in schools, daycare centers, and hospitals. The virus has also been associated with fetal damage (hydrops fetalis), aplastic crisis, and arthralgia.(2-4) Infection during pregnancy risks transmission to the fetus, which may cause intrauterine death. The rate of fetal death following maternal infection ranges between 1% and 9%.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

IgG: <0.9

IgM: <0.9

Interpretation Provides information to assist in interpretation of the test results

Specimens with an index of <0.9 are considered negative.

 

Specimens with an index of >1.1 are considered positive.

 

Specimens with an index between 0.9 and 1.1, inclusive, are considered equivocal.

 

Parvovirus B19 IgM

Parvovirus B19 IgG

Interpretation

Negative

Negative

Implies no past infection/patient may be susceptible to B19V infection

Negative

Positive

Implies past exposure/infection-minimal risk of B19V infection

Equivocal

Positive or negative

May indicate current or recent B19V infection-retest in 1 to 2 weeks

Positive

Positive

Implies current or recent B19V infection

Positive

Negative or equivocal

May indicate current B19V infection-retest in 1 to 2 weeks

 

The presence of IgM class antibodies indicates recent infection. The presence of IgG antibodies only is indicative of past exposure.

 

Both IgG and IgM may be present at or soon after onset of illness and reach peak titers within 30 days. Because IgG antibody may persist for years, diagnosis of acute infection is made by the detection of IgM antibodies.

 

The prevalence of parvovirus B19 IgG antibodies increases with age. The age-specific prevalence of antibodies to parvovirus is 2% to 9% of children under 5 years, 15% to 35% in children 5 to 18 years of age, and 30% to 60% in adults (19 years or older).

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Specimens drawn prior to seroconversion may yield negative IgM and IgG antibody results, while specimens drawn after IgM antibody levels have begun to decline may yield negative IgM antibody results. The results of a single assay or a combination of IgM and IgG EIAs should not preclude additional testing, ie, follow-up specimens from the patient 1 to 4 weeks following the initial test.

 

Test results of specimens from immunocompromised patients may be difficult to interpret.

 

Testing should not be performed as a screening procedure for the general population.

 

Specimens containing antinuclear antibodies may produce equivocal or positive test results in the IgM assay.

 

Epstein-Barr virus-positive specimens may produce positive or equivocal test results in the IgM assay.

Clinical Reference Provides recommendations for further in-depth reading of a clinical nature

1. Brown KE, Young NS: Parvovirus B19 in human disease. Ann Rev Med 1997;48:59-67

2. Markenson GR, Yancey MK: Parvovirus B19 infections in pregnancy. Semin Perinatol 1998;22(4):309-317

3. Summers J, Jones SE, Anderson MJ: Characterization of the genome of the agent of erythrocyte aplasia permits its classification as a human parvovirus. J Gen Virol 1983;64;(Pt 11):2527-2532