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Negative Fiji's test

Introduction
Cause
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Diagnosis

Introduction

Introduction The external Fischer test uses a non-specific agglutination reaction with Proteus OXl9, OX2, and OXK which share a common bacterial antigen with rickettsia, and detects the presence or absence of rickettsial antibodies in the serum of the patient. The external Fischer test is also known as the Proteus agglutination test for the diagnosis of epidemic typhus, ascariasis and other acute infectious diseases. After the human body is infected with rickettsia, the corresponding antibodies are gradually produced in the serum. The antibody appears 5 to 12 days after the onset of the disease, and disappears after several months. The common rickettsial disease in China is typhus and tsutsugamushi. The epidemic typhus is mainly caused by the increase of OX19 agglutination price. The main manifestation of tsutsugamushi disease is OXK.

Cause

Cause

Reasons for the negative Feis test:

After the human body is infected with rickettsia, the corresponding antibodies are gradually produced in the serum. The antibody appears 5 to 12 days after the onset of the disease, and disappears after several months. Generally, the agglutination price is above 1:160 or the titer is significantly increased during the course of the disease. Diagnostic significance. The common rickettsial disease in China is typhus and tsutsugamushi. The epidemic typhus is mainly caused by the increase of OX19 agglutination price. The main manifestation of tsutsugamushi disease is OXK.

Epidemic typhus (100% positive rate of OX19); endemic typhus (OX19 part can be 1:200 ~ 1:800); patients with scrub typhus (14% of Oxk in the first week after illness is 1:80) Above, up to 80% in the fourth week); brucellosis, return to heat patients; pregnant women slightly increased.

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an examination

Related inspection

Blood routine virus infection immunoassay

Diagnostic examination of negative Feis test:

Normal human titer (serum dilution factor) does not exceed 1:20

(1) increase: epidemic typhus (OX19 positive rate can be 100%); endemic typhus (OX19 part can reach 1:200-1:800); tsutsugamushi loyalists, OXK in the first week after illness 14% are above 1:80. The fourth week can reach 80%.

(2) The titer in serum of patients with brucellosis and recurrent fever also increased. Pregnant women can increase slightly.

Reference value: Slide agglutination method: OX2<1:160OX19<1:160OXK<1:160

Complement binding test: negative

Immunofluorescence staining: negative

Diagnosis

Differential diagnosis

Differential diagnosis of negative Feis test:

It should be differentiated from typhoid fever, typhus, anthrax, bubonic plague, and leptospirosis.

(1) The typhoid fever is slow, the expression is indifferent, there are a few rose rashes, no eschar ulcer, blood culture has typhoid bacillus growth, fat Dar's reaction is positive, and the external Fibonacci reaction is negative.

(2) Typhus rash is more common in winter and spring, no eschar and local lymph node enlargement, Philippine reaction OX19 positive, OXk negative, Platts or Morse rickettsia as antigen for complement fixation test positive.

(C) Leptospirosis disease The gastrocnemius pain is obvious, no eschar, ulcer and rash. Leptospira can be found in blood. The Leptospira complement fixation test positive for positive and latex agglutination tests.

(4) Skin anthrax has a history of exposure to livestock. The lesions are more common in exposed parts. The symptoms of venom are mild, no rash, and the total number of white blood cells in the blood increases. The secretions can be found in Bacillus anthracis, and the external Fibonacci reaction is negative.