Legionnaires' disease is a newly discovered respiratory infectious disease in the past 20 years. Its pathogens are widely distributed in nature and the mortality rate is high. In China, the earliest cases of Legionnaires' disease were discovered in 1982, and Legionella pneumophila was isolated from the patient's sputum, lung tissue and hotel cooling tower air-conditioning water, which was still popular in a small range. Legionella has special requirements for growth conditions, and the culture and identification cycle is longer, so serological examination is an important indicator for the diagnosis of this disease.

Basic Information

Specialist classification: Infectious disease inspection and classification: pathogenic microorganism inspection

Applicable gender: whether men and women apply fasting: fasting

Analysis results:

Below normal:

Normal value:
no

Above normal:

negative:
Not infected with Legionella.

Positive:
Tips may be infected with Legionella.

Tips: The optimal time to collect specimens: within 7 days of acute phase and 21 to 42 days of recovery, but combined with clinical analysis. Zuravleff et al reported that about one in four patients had a significant increase in antibody titers after 1 week of onset. When the disease is suspected, the serum is taken immediately, and the result is taken as the baseline if it is higher than the basal level of the population in the area. Normal value

O < 1:80.

H < 1:160.

A<1:80.

B < 1:80.

Clinical significance

The positive rate of patients with Legionnaires' disease is 75% to 85%. In the acute phase and recovery phase, the serum concentration was ≥ 4 times, and the titer was ≥ 1:160, or the single serum ≥ 1:320 had diagnostic value.

Positive results may be diseases: Legionella pneumonia, Legionella disease considerations

The optimum time to collect specimens:

The acute phase is within 7 days, and the recovery period is 21 to 42 days, but it needs to be combined with clinical analysis. Zuravleff et al reported that about one in four patients had a significant increase in antibody titers after 1 week of onset. When the disease is suspected, the serum is taken immediately, and the result is taken as the baseline if it is higher than the basal level of the population in the area. A single measurement is diagnostic. The specific therapeutic response to erythromycin is available for diagnostic reference.

Inspection process

(1) Take 15 rows of 10mm × 100mm test tubes, 8 per row, and add 0.5ml of physiological saline.

(2) Take another 15mm × 150mm test tube, add 9ml of normal saline and 1ml of serum to be tested, and mix it to become 1:10 diluted serum. Add 0.5 ml each in the first tube of each row.

(3) The first tube of each row was started, and the ratio was diluted to the sixth tube. The seventh tube was used as a serum-free control solution, and the eighth tube was used as a positive control.

(4) Add 0.5 ml of Lp1-Lm antigen solution to each tube, mix well, and observe the results in a 37 °C water bath for 18-24 hours.

Not suitable for the crowd

Those who do not have an indication for examination should not do this check.

Adverse reactions and risks

1, subcutaneous hemorrhage: due to pressing time less than 5 minutes or blood draw technology is not enough, etc. can cause subcutaneous bleeding.

2. Risk of infection: If you use an unclean needle, you may be at risk of infection.