After 12 days of onset of typhoid fever and paratyphoid fever, specific antibodies were produced in the serum and gradually increased to reach the peak at 4 weeks, and then gradually decreased. The fat reaction, also known as typhoid serum agglutination test, is a serological test for the diagnosis of typhoid and paratyphoid to check the antibody titer in serum and its growth rate.

Basic Information

Specialist classification: Infectious disease examination and classification: blood examination

Applicable gender: whether men and women apply fasting: fasting

Tips: On an empty stomach, tell your doctor about the history of vaccination. Normal value

O:O ~ 1:80 (0 to 1:80).

H:O~1:160 (0 to 1:160).

A: O ~ 1: 80 (0 ~ 1: 80).

B: O ~ 1: 80 (0 ~ 1: 80).

C:O ~ 1:80 (0 to 1:80).

Clinical significance

(1) Raise:

1O, H agglutination price are increased, can diagnose typhoid fever.

When 2C and one of A, B, and C increase the agglutination price, it can diagnose paratyphoid A or B or C.

3H agglutination price increases and O agglutination price is not high.

A. Those who have been inoculated with typhoid vaccine.

B. Those who have suffered from typhoid fever.

C. A very small number of patients with typhoid fever are not increased due to the influence of the O antigen on the O agglutination.

D. Other Salmonella infections.

(2) Note:

1 The first week of onset is 50% positive, the second week is 80% positive, and the fourth week is more than 90% positive, so it should be checked multiple times. If the agglutination price increases with the course of the disease, it has diagnostic value (early and late course) .

2 Negative reaction can not rule out typhoid fever, about 10% of patients with typhoid fever are always negative.

3 should be blood, bone marrow, urine, fecal bacteria culture.

High results may be diseases: typhoid and paratyphoid fever, paratyphoid fever, palpitations, citrate pneumonia, precautions for fever in children

Requirements for inspection:

(1) A small number of typhoid patients may have a negative reaction to the "O" antigen in the whole course of disease, especially those with malnutrition and antibody immunodeficiency, as well as children with impaired immune function, or patients with early use of large amounts of antibiotics may have false negatives.

(2) I have received typhoid fever, paratyphoid vaccine injection, infection with brucellosis or influenza, H agglutination price can be increased, O agglutination price is lower.

(3) Mycobacterium tuberculosis, sepsis, infectious hepatitis, and other Salmonella infections may sometimes have high agglutination valence, which is a false positive.

(4) The agglutination price of this test can not be used as a criterion for judging the efficacy of typhoid fever and paratyphoid fever.

Preparation before inspection:

On an empty stomach, tell the doctor about the history of vaccination.

Inspection process

1. Take the Kang's test tube and arrange it into 5×7 form. The 5 rows are respectively arranged into O, H, A, B, and C.

2. Take another large test tube, add 0.25ml of the patient's serum, dilute 1:25 with 4.75ml of normal saline, and take 2.5ml of the diluted serum into 0.5ml of each row of the first tube.

3. Take 2.5ml of normal saline and dilute the serum in the large test tube twice. Take 2.5ml of the diluted serum into 0.5ml of each row of the second tube, and so on. Add 0.5ml of normal saline to the last tube of each row. Negative control, each dilution: 1/20, 1/40, 1/80, 1/160, 1/320. Then, 0.5 ml of each 1:10 diluted solution was added to the first six tubes, and the final dilutions were: 1/40, 1/80, 1/160, 1/320, 1/640.

4. Shake well and mix and place at 37 ° C for 16-20 hours.

Not suitable for the crowd

Not suitable for people:

Malnutrition and antibody immunodeficiency.

Adverse reactions and risks

There are no related complications and hazards.