Blood Testing In The Laboratory
The laboratory is one sensitive part of the organization as it is faced with the duty of making valid results available to health sectors (medical centers, hospitals etc) for proper diagnosis and relevant prescription of drugs to patients.
PACKED CELL VOLUME
AIM:- To determine the percentage of the total volume of whole blood occupied by packed red cells.
PRINCIPLE: - Erythrocyte is packed together when spin at high speed at a time interval.
MATERIALS:- Capillary tube, blood sample, dry cotton wool, Bunsen burner flame, micro haemostatic reader, haemostatic centrifuge.
PROCEDURE:- Fill the capillary tube 2/3 full either with well mixed venous blood or directly from capillary puncture. Seal one end of the capillary tube using Bunsen burner flame. Ensure it is properly sealed by inverting to check for flow of blood. The filled tube is then placed in the micro haemostatic centrifuge and spin at 10.000rev for 5 minutes.
RESULT:- Read using the micro- haemostatic reader. Normal range result includes the following:
Female 35 – 45%
Male 45 – 55%
Infant 35 – 45%
Neonates 45 – 65%
A.B.O BLOOD GROUPING TEST
AIM:- To determine the blood group of an individual
PRINCIPLE: - Antibody – Antigen reaction.
MATERIAL; - ABO Grouping Anti Sera, tile, blood sample.
• Get a clean grease free white tile.
• Place one drop of the patient’s blood sample on each of the anti-sera.
• Mix the blood and anti-sera using a separate application stick.
• Rock the tile gently and read after five minutes.
Agglutination result signifies a positive reaction / blood group.
Patient Anti-A Anti-B Anti-D Result
1 + - + A Rh’D Positive
2 + - - A Rh’D Negative
3 - + + B Rh’D Positive
4 - + - B Rh’D Negative
5 - - + O Rh’D Positive
6 - - - O Rh’D Negative
7 + + + AB Rh’D Positive
8 + + - AB Rh’D Negative
N.B - Anti A is blue in color
Anti B is Yellow in color
Anti D is Straw or White in color
AIM:- To separate and identify the hemoglobin genotype of an individual.
APPARATUS: - Blood sample, As control, cellulose acetate paper, electrophoresis machine, Absorbent paper, little cover slip, water, micro pipette.
PRINCIPLE:- Rapid movement or migration of hemoglobin of normal cell in an electric field.
• Wet an acetate paper with buffer solution; dry it in between folded absorbent paper.
• Place a drop each of the patient blood and the control as sample on a white tile.
• Pipette one or two drops of water on each of the dropped blood and mix thoroughly to lyses the red blood cell.
• With the edge of a tiny cover slip, dip into the mixed blood and make bands on the acetate paper close to the edge on a straight line.
• Place the paper in the electrophoresis machine with buffer water inside the machine and cover.
Bands separate after a few minutes. The component of the blood separates by chromatographic movement on the acetate paper.
AS - Two bands, one on top and the other below.
AA - Two bands both above.
SS - Two bands both below.
MALARIAL PARASITE TEST
AIM: - To detect malaria parasite in the blood.
MATERIAL: - Microscope, slide, blood sample, and field stain A and B, immersion oil, EDTA container, syringe.
• Collect blood sample from the patient and put it in an EDTA container.
• Put a little quantity of blood on a clean, grease free slide.
• With the aid of a spreader, smear the blood round the area till a kobo shape is achieved.
• Allow to air dry while standing on a rack.
• Place in a rack flood with 10% germs stain and allow acting for 10 minutes.
• Rinse with water after 10 minutes.
• Wipe the back of the slide with an absorbent cotton wool.
• Allow to air dry.
• View under the microscope by placing a drop of immersion oil on a centre of the smear using x 100 objective.
RESULT: - Ring form or gametocyte of malaria parasite indicates malaria infection.