Hello everyone, very sorry for my late posting (:

Alright, as you all know that in my lab, we rotate around for a few weeks, and so finally, at the final and permanent department, I am posted to Microbiology department.

In Micro lab, as everyone knows, we do growth of microbes, smears for identifications, and also serology. And serology is so called my section because I am fully in-charged in doing it (my micro department only got 2 person, me and my supervisor).

Serology tests that is in my section will be VDRL, TPHA, Mycoplasma, ASOT, Monotest, WWF etc. All of these tests make use of the principle of agglutination antibodies against the reagent antigens. Now, I am going to describe to you one of the test mentioned above, WWF.

WWF? I bet you must be laughing that its something that got to do with wrestling... that's what I thought initially too. Ok, WWF stands for Widal & Weil Felix test. It is actually two different test looking for the specific antibodies against antigens of microorganism. It is a quantitative test where the titre of the antibodies will be determined.

Widal test

Test for agglutinating antibodies against antigens of O-somatic and H-flaggella (they are the antigenic factors) in the serum when there is a Salmonella infection. It is a presumptive test for Enteric fever also known as Typhoid fever and undulant fever which is caused by Salmonella enterica serotype typhi. It can be spreaded or acquired by contamination of the food where it will enter the gastro-intestinal tract and migrate to other parts of the body through the bloodstream.

Weil Felix test

Test to determine the infection with a species of Rickettsia where the certain strain of Proteus Vulgaris form agglutinin with serum of those infected individuals. Rickettsia species are carried as parasites on ticks, fleas and lice. They are the cause of Typhus, rickettsialpox etc. Because the somatic constituents of some strains of Proteus are shared with some species of Rickettsia, hence, there will agglutination with proteus strains in patient with Rickettsia infection.


Materials

There is a total of 11 reagents to be used for this test. For the Widal test, reagent 1 to 8 is used which consist of,

1. Salmonella O Typhi
2. Salmonella O Paratyphi A
3. Salmonella O Paratyphi B
4. Salmonella O Paratyphi C
5. Salmonella H Typhi
6. Salmonella H Paratyphi A
7. Salmonella H Paratyphi B
8. Salmonella H Paratyphi C

These reagents above, contain the antigens specific to the antibodies that the body produce if there is any infection. As mentioned, O and H are the antigenic factors of Salmonella bacteria. The A, B and C are the typing that will determine which type is involved in the infection.

For Weil Felix test, the reagent 9 to 11 are used which consists,

9. Proteus OX2
10. Proteus OX19
11. Proteus OXK

These reagents above are stained Proteus species suspensions that will react with patient serum if they are infected with the Rickettsia species where antibodies of Rickettsia will be reacted.

Methods

Patient's serum is used for this test.
1. 20ul of the patient serum is placed on 11 circles on the RPR card and labelled accordingly. (Look below)


Picture taken from: http://www.bd.com/ds/images/products/img_rprcard_200px.jpg

• If non-reactive, they'll be reported as 1:20 (titre of antibody)
• If anyone of the circles are reactive, futher investigations will be done with 10 and 5ul. This is to determine the reactivity of the serum with the reagent
• The circle that is reactive will be repeated with 10 and 5ul of serum with the specific reagent that has the reaction. (Eg. Circle 1 - reagent 1: Positive, so reagent one will be repeated again on 10ul and 5ul of serum)
• If it is only positive on 20ul and not 10 and 5ul, it will be recorded as 1:80.
• If it is positive on 10ul and not on the 5ul, it will be recorded as 1:160
• If it is postive on 10ul and 5ul of the serum, it will be recorded as 1:320 (highest which indicates infection of the specific bacteria species)

So basically, the lower the amount of serum and yet there is reaction, the higher the titre of antibodies.

After determining the titre or amount of antibodies, we will report to the doctors or respective clinics so further investigations can be done to the patient (:

So that's all for this test, I've actually done this test on my own sera before, and I AM POSITIVE FOR THE WEIL FELIX test. But my supervisor say it is ok. I don't even know when I got it.

Alright, hope you all understand what I wrote. Feel free to ask me any questions (:

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