Diaspot Tb Test and Quality Control
Tuberculosis eapid test device
A rapid test for the qualitative detection of anti TB antibodies in blood, serum or plasma specimen this test only indicates the presence of anti-TB antibodies in the specimen and should not be used as a criteria foe the diagnosis of active tuber gnosis. Neither the qualitative value non the rate of increase in anti-TB antibodies concentration can be determined by this qualitative test.
Principle:- The tuberclosis rapid test device is rapied test for qualitative solid immunoassay for the detection of anti-TB antibodies (Isotype lgG, lgM and lgA) in whole blood, serum or plasma specimen.
The membrane of the test device is percolated with TB-recombinant antigen on the test line region of the device. During testing, Anti-TB antibodies, if present in whole blood serum or plasma specimen react with the particle coated with TB recombinant antigen. The mixture migrates upward on the membrane by capillary action to react with TB recombinant antigen on the membrane and generate colored line.
- Test device (strip - Buffer)
- Blood specimen
Procedure:- venipuncture blood specimen ie anti coagulated blood sample was collected from a patient’s finger and its drops was introduced into the specimen well of the test strip. A drop of buffer was also added and allows to move by capillary action in the strip for some seconds.
Positive:- Two distinct colored line appear one line should be in the control region C and another line should be in the test region T.
Negative:- One colored line appears in the control region C. No apparent colored line appears in the test region T.
Invalid:- Control line fails to appear. This may be due to insufficient specimen volume or incorrect procedural techniques.
- I ensured that reagents are not used after expiring date
- I ensured that protective clothing were put on to avoid been untanimated while carrying out the test.
- I ensured that normal humidity and temperature are maintained.
Zainesing Staining Method
Sputum staining for AFB (Acid fast basalide) bacteria material/reagent –solution of carbol fichsin cone, methylene bluem glass slide, wire loop, 3% acid alcohol wooden or metal rack, Bunsen bumer or spirit lamp, microscope.
Clearance slides free from breeze and scratches with wire loop, take small portion from pulient part of sputum make a smear on the centre of the slides not to be two thick or thin. Allows to dry with cool air. After drying fix the slides ion the rack by passing flame under it three times. Then cover with about 5-10ml of carbol fichsin concentration.
With flame, heat the slides until the steam rises not to allow it to boil or to dry. Time for about 15 minutes then discolourize with 3% acid alcohol and raise with clean water until it becomes colourless. Cover with mathylene blue concentration for 2 minutes and raise with water and stand the slides slantly and allow to dry.
It is then examine with microscope adjusted to X100 power lense after addition of one drop of oil emmersion to increase the refractive index of the specimen observation/result-AFB Bacteria appear nod shape stain red in the sputum if present.
This is because AFB retains the colour of carbol fichsin concentration.
Concentration-Tuberclosis is a transmittable and buller disease. I therefore advice any person who is observing symptoms of constant coughing to go for TB test.
HEPATITIS B VIRUS
Viral hepatitis is a systematic disease that most invade in the liver. Hepatitis are caused by hepatitis virus, hepatitis B virus or hepatitis C virus. The lomplex antigen found on the surface of hepatitis B antigen (HBsAg). The presence of HBsAg in serum or plasma is an indication of an active hepatitis B infection.
Typical hepatitis B (HBsAg) is detected 2 to 4 week before the Alamine transferase ALT and Aspartate transferase AST level become abnormal and symptoms are detected between 3 to 5 weeks. Hepatitis B has 10 major serotype because of antegenis heterogeneity of the determinant.
One step hepatitis B surface antigen test strip (serum/plasma)
This is a rapid test qualitative detect the presence of HBsAg in serum or plasma specimen. The test utilizes a combination of monoclonal and polyclonal antibodies to selectively detect elevated levels of HBsAg in serum of plasm.
The HBsAg one step hepatitis B surface Antigen test strip is a lateral flow immunoassay for the detection of HBsAg in serum or plasma.
The membrane is pre-coated with anti- HBsAg antibodies on the test line region of the strip. During testing, the serum or plasma specimen react with the particle coated with anti HBsAg antibody. The mixture migrate upward on the membrane by capillary action to react with anti- HBsAg antibodies on the membrane and generate a colored line. The presence of this colored line in the test region indicates a positive result and its absence indicates negative result.
The test strip contains anti- HBsAg prticles and anti- HBsAg coated on the membrane.
SPECIMEN COLLECTION AND PREPARATION
A sample of blood was collected from a patient and centrifuge to separate the anti coagulated blood, serum and plasma. The separation should be quick to avoid hemolysis. The testing should be performed with non-hemolyzed and should not be kept at room temperature for long time. The specimen can be stored at 2-8OC for up to 3 days.
- Prepared serum or plasma specimen
- Test Strips
Bring the ponch of test strip to a room temperature and remove the test from the sealed ponch.
Immerse the test strip vertically in the prepared serum or plasma for at least 10-15 seconds. Do not pass the maximum line (max) on the test strip when immersing the strip.
Too distinct red lines appear. One time should be in the control region C and another line should be in the test region T.
NOTE- The intensity of the red color in the test line region T may vary depending on the concentration of HBsAg present in the specimen.
Negative- One red line appear in the control region.
Invalid- Control line fails to appear
A procedural control is included in the test. As real line appearing in the control region C is the internal procedural control. It confirms sufficient specimen volume and correct procedural techniques.
Hepatitis B, Diaspot Tb Test and Quality Control