Parvovirus B19 IgG and IgM

Does a child at nursery have bright red cheeks and a rash while you are pregnant? Or did your hand joints become painful after a cold? Parvovirus B19 antibody testing shows previous infection and protection, while positive IgM suggests a possible recent infection.

Who the test is for

• pregnant women exposed to a child or adult with fifth disease or an unexplained rash;
• pregnant women whose ultrasound shows fluid accumulation or signs of fetal anaemia;
• women planning pregnancy who work with young children, for example in nurseries or schools;
• adults with sudden pain and swelling in hand, wrist or knee joints, particularly after contact with a sick child;
• people with inherited anaemia, such as sickle cell anaemia or spherocytosis, with a sudden haemoglobin fall.

If someone with inherited anaemia suddenly becomes very pale, weak and breathless, call emergency assistance immediately (194 or 112).

What the test reveals

Parvovirus B19 causes fifth disease (erythema infectiosum), a common childhood illness with red cheeks and a lacy rash on arms and legs. It spreads by droplets. In adults it more often causes joint pain than a rash, and many have no symptoms. About half of adults are already protected.

The virus temporarily stops red blood cell production. Healthy people do not notice this, but it can cause severe anaemia in fetuses, people with inherited anaemias and those with weakened immunity.

• IgM appear around ten days after infection and usually disappear in two to three months, sometimes persisting up to six months.
• IgG appear somewhat later and remain for life, indicating protection.

The procedure and preparation

Blood is taken from a vein, taking a few minutes. No fasting or special preparation is needed. If pregnant, state your pregnancy week and when contact with the infected person occurred.

What your result means

• IgG positive, IgM negative: you are protected, so contact with an infected child generally poses no risk.
• IgG and IgM negative: you are unprotected. If exposure occurred during pregnancy, a doctor usually repeats testing after two to four weeks.
• IgM positive: suggests current or recent infection. IgM can also be falsely positive, so testing is sometimes repeated. During pregnancy a gynaecologist then monitors the fetus with ultrasound over the following weeks.

Thresholds are printed on the report. A doctor, or a gynaecologist in pregnancy, interprets results alongside symptoms, contact timing and pregnancy week.

How to arrange testing

You can have blood taken without an appointment or referral at one of our branches across Croatia (listed under Contact). Prices for all tests and panels are available in the price list. Parvovirus is not included in the TORCH test, so it is tested separately in pregnant women.

Frequently asked questions

Is parvovirus dangerous in pregnancy?

Usually not: most pregnancies after infection have no lasting consequences. The risk is higher in the first half of pregnancy, when the virus can cause fetal anaemia. A gynaecologist therefore monitors the fetus with ultrasound; fetal anaemia can be treated at a specialist centre.

Is a child with fifth disease infectious?

Most infectious before the rash, when they have only mild cold-like symptoms. Once the rash appears they are usually no longer infectious, so a child feeling well can return to nursery or school.

Can parvovirus occur twice?

Past infection provides lifelong protection, so repeat illness is very rare. Positive IgG with negative IgM therefore reassures pregnant women after contact with an infected child.

How long does joint pain last?

Usually one to three weeks, sometimes several months. It most often resolves without lasting effects. If joints continue swelling, a doctor investigates other causes.