Mycoplasma in children is weakly positive

When taking care of children, the thing mothers worry about most is that their children will suffer from some diseases. When children have a cough that recurs and is not very good, it has affected the children's normal life. Parents should take the children to the hospital for examination. If the doctor asks to check for mycoplasma, many parents will worry that the children have pneumonia. In fact, pneumonia is only possible when the test result is positive.

What does mycoplasma antibody positive weak positive mean?

After Mycoplasma pneumoniae infects the human body, it goes through an incubation period of 2 to 3 weeks. After the incubation period, clinical manifestations will appear. Most patients show symptoms of pharyngitis, rhinitis, tracheitis and bronchiolitis. In severe cases, mycoplasma pneumonia may occur. About 1/3 of cases may also be asymptomatic. Mycoplasma pneumonia has a slow onset, with early symptoms including sore throat, headache, fever, fatigue, muscle aches, loss of appetite, nausea, and vomiting. The fever is generally moderate, and obvious respiratory symptoms appear after 2 to 3 days, with paroxysmal irritating cough, which is more severe at night, and a small amount of sticky sputum or mucopurulent sputum, sometimes with blood in the sputum. There may also be difficulty breathing and chest pain. The fever may last for 2 to 3 weeks, and cough may still occur after the body temperature returns to normal.

In short, after children are infected with mycoplasma, most of them will show symptoms such as fever and cough, and only about 3% to 10% of mycoplasma infected people will develop mycoplasma pneumonia. Therefore, it cannot be said that a positive test for Mycoplasma pneumonia means Mycoplasma pneumonia. Generally speaking, as long as the chest X-ray is normal, there are no shadows, and there are no other discomforts in the body, there will not be any big problems even if the IgG antibody test result is positive.

How to read the test report of Mycoplasma pneumoniae

1. Direct culture method:

The specimen can be collected from the sputum or throat swab of the suspected patient, inoculated into an agar medium containing serum or yeast extract, and then observed. The result is generally reported directly as positive or negative.

2. Serological diagnosis:

A venous blood sample is required. The complement fixation test using patient serum and mycoplasma lipid antigen shows that the titer in the recovery phase is more than 4 times higher than that in the acute phase, which has diagnostic value. The general reports are 1:40, 1:80, 1:160, etc., and above 1:80 is meaningful.

3. Serum antibody test:

Venous blood needs to be collected to check specific IgM and IgG, which has high specificity and sensitivity. When the human body is infected with Mycoplasma pneumoniae, it can produce specific IgM and IgG antibodies. IgM antibodies appear early, usually one week after infection, reach a peak at 3 to 4 weeks, and then gradually decrease. Since the incubation period of Mycoplasma pneumoniae infection is 2 to 3 weeks, when patients develop symptoms and seek medical treatment, IgM antibodies have reached a fairly high level. Therefore, positive IgM antibodies can be used as a diagnostic indicator for acute infection. If the IgM antibody is negative, the Mycoplasma pneumoniae infection cannot be denied and IgG antibody testing is required. IgG appears later than IgM and needs to be observed dynamically. If it increases significantly, it indicates infection, while if it decreases significantly, it indicates the late stage of infection.

4. Genetic diagnosis:

The sensitivity of using DNA probes to diagnose mycoplasma is slightly lower, but the specificity is high. The polymerase chain reaction (PCR) has both high sensitivity and specificity. It is currently rarely used in hospitals.