Widal test is a
test conducted in the laboratory for diagnosis of different type of species and
sub species of salmonella that cause typhoid fever. There are different species
and sub species of salmonella but it only few of them that cause typhoid fever.
The following are the species and sub species of salmonella that cause typhoid
fever in human being when ingested either trough water or uncooked food or
contaminated hand. examination of bacteria
1.
Salmonella typhi O and H
2.
Salmonella paratyphi A
3.
Salmonella paratyphi B
4.
Salmonella paratyphi C
WIDAL TEST KIT
REAGENT
COMPOSITION
Salmonella.
typhi H 1 x 5ml
Salmonella. typhi
O 1 x 5ml
Salmonella.
paratyphi A-H 1 x 5ml
Salmonella.
paratyphi A-O 1 x 5ml
Salmonella.
paratyphi B-H 1 x 5ml
Salmonella.
paratyphi B-O 1 x 5ml
Salmonella.
paratyphi C-H 1 x 5ml
Salmonella.
paratyphi C-O 1 x 5ml
PREPARATION
The reagent are
already made, and is commercially available in the store that sale laboratory
reagent across the world.
VARIETIS
There are many
companies that produce the reagent, and each of the reagent names is based on
the company name that produced it. Bellow is some of the reagent provided with
different company names;
1.
Cromatest widal kit reagent
2.
Omega widal kit reagent
3.
Acumen widal kit reagent
SAMPLE
A whole blood is
collected then serum is separated from the red cell packed, the separated serum
is the sample used to carry out the serological test for typhoid fever.
PROCEDURE
1.
Collect a whole blood of 3-4ml volume
2.
Discard the blood into EDTA tube container
3.
In the absent of EDTA container, fluoride oxalate, or
sodium heparin container can be used
4.
After discarding the blood in the container, cover it,
invert the blood gentle to mix blood with the anticoagulant inside the
container, then take the sample to bucket centrifuge, place it in the
centrifuge used equal volume of blood or other fluid place it on the opposite
of the blood sample in the centrifuge in other to balance the centrifuge when
spinning to avoid unwanted vibration.
5.
Set the time on the centrifuge to 10 minute, and set
the speed to 60rpm, then switch on the centrifuge.
6.
Allow the blood to spin until the centrifuge stop,
allow the rotating motion to come to rest, then open the centrifuge and bring
out the blood sample.
7.
In the absent of centrifuge the sample can be left on
the working table for same time to sediment, after that the supernatant is
separated from the red cell packed into a plain container.
8.
When the blood is clearly separated, a clear fluid of
plasma is on the top, buffy coat on the center separating the red cell with the
plasma. See picture bellow;
9.
On a clean grease free dry white tire, dispense volume
per volume of the widal kit reagent on the tire, as shown on the table bellow;
10.
After dispensing the reagent as shown in the table
above, the add your sample as shown in the table bellow;
11.
Dispense your reagent and serum as illustrated on the
table above, mix the reagent and the sample together using needle cap or any
available mixing stick.
12.
After mixing, your tire should resemble table bellow;
13.
After mixing as shown in the table above,
14.
Set your stop watch to 2 minute, then start rocking the
tire and be checking constantly.
15.
Any agglutination seen when rocking, time of seen the
agglutination should be noted.
16.
Stop rocking when the stop watch top.
PEPORT YOUR
RESULT AS FOLLOW
When
agglutination seen within 0 – 30 second = 320
When agglutination
seen within 30second – 1 minute = 240
When
agglutination seen within 1minute – 1minute 30 second = 160
When
agglutination seen within 1minute 30 second – 2minute = 80
When no
agglutination seen, then record your result as follow;
1:20 1:20 1:20 etc. the format should be as shown
in the table bellow
S.TYPHI
&
SERUM
|
S.P. TPHI A
REAGENT &
SERUM
|
S.P. TPHI B
REAGENT &
SERUM
|
S.P. TPHI C
REAGENT &
SERUM
|
|
O
|
1:20
|
1:20
|
1:20
|
1:20
|
H
|
1:20
|
1:20
|
1:20
|
1:20
|
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