Serology Practice in Medicine

Serologic Test

 Serologic test are body fluid test that deals with  looking for antibodies in a patient's blood there are different serological test for different diagnosis but they have one thing in common with focusing on protein made by immune system.

Note

Antigen: The are substance that provoke the response of the immune system

Antibody: These are substance produced by immune system in response to antigen in order to deactivate them.

Types of Serological test includes:
1) Agglutination.
2) Precipitation.
3) Complement Fixation test e.t.c.
Diseases diagnosed using serologic test include:
1) Widal test
2) Hepatitis B
3) Hepatitis C
4) Syphilis
5) Tuberculosis
6) Pregnancy e.t.c

Widal Test

Widal test can be defined as an agglutination test whicha helps to detect the presence of serum agglutinins (H and O) in patients serum with typhoid and paratyphoid fever.

Material/Reagent used

1) Serum/Plasma
2) Suspended Antigen D,A,B,C (OH)
3) Slide
4) Disposable pipette
5) Sticks
6) Stop watch
7) Centrifuge

PROCEDURE

1) Get the blood sample and spin to get plasma or allow to settle in syringe to get the serum.
2) Get the slide, stick and suspended atigen ready
3) Transfer 50microliter of serum to four circles for respective circles.
4) Place one drop of the antigen suspension into the corresponding circle
5) Mix contents of each circle uniformly over the circle with separate sticks
6) The slide is then rocked gently to and fro for few minutes not more than four minutes.
7) Observation

RESULT

Present of agglutination Typhoid is positive
Absence of agglutination Typhoid is negative


Rapid test for some serologic test

Rapid tests are a simplified and fast method of antibody ELISA tests. They look for antibodies in the blood. They are fixed on one particular strip along the rapid test stick. Towards the end of the testing stick are control antigens to show that the test worked.

This test can be used to diagnose the following

Hepatitis B
Hepatitis C
Tuberculosis
Syphilis.
This can be carried out with serum/plasma and also with whole blood using venipuncture and capillary blood collection respectively.

Material/Reagent Used

1) Full blood or Serum/Plasma
2) Rapid Test Strip
3) Disposable pipette
4) Buffer
5) Stop Watch
                         

Procedure for rapid test using serum/plasma

1) Collect Blood sample
2) spin or allow to separate
3) Open the rapid test strip
4) Handle the strip properly and carefully
5) Deep the strip properly into the plasma or put the serum on the strip with a syringe
6) Set your stop watch for Fifteen (15) minutes
6) If strip is being dipped into the plasma allow for two (2) minutes then bring it out
7) Observation
8) Allow for complete 15 minutes to avoid error and observe again.

Procedure for rapid test with whole blood

1) Clean the site of blood collection
2) Open the rapid test strip
3) Handle strip with care
4) Pierce and apply little pressure to make the blood flow
5) Put whole blood on the strip then put buffer solution immediately
6) Allow it to go down the strip
7) Observation

Result

If two lines becomes visible one at the patient's side and one at the control side that means patient is POSITIVE but if only a line appears which is on the control side it means patient is NEGATIVE. When no line appears or it appears only on the patient's side it means ERROR