How To Prepare Field Stain A and B

Field Stain's are used widely for detection of malaria parasite. It is readily available and  is used in staining of blood smears. The use of field stains gives specific diagnosis for malaria parasite present in the blood film at an affordable cost.

The staining method involves the use of both Field Stain A and Field Stain B, which are water soluble and can be prepared easily by commercially available stain powder.  It should be ensured that the solutions are prepared using standard preparation procedure.

The staining is done to identify the malaria parasite through microscopic diagnosis. The patient's blood smear is prepared on a microscopic slide and stained using the Field Stain A and B following standard procedure. Usually both thick blood films and thin blood films examination is carried out for the diagnosis of parasite. Thick blood film examination is usually recommended for diagnosis of malaria parasite in addition to thin blood film examination in case of low level of malaria parasite in blood. It is recommended to follow the guidelines to carry out the microscopic examination of the Field's stained thick and thin blood films.

Preparation of Field's Stain A Solution:

1) Dissolve 2.6 g of anhydrous disodium hydrogen phosphate(Na₂HPO₄)(Article No. 5974C)  and 2.6 g of potassium dihydrogen phosphate (KH₂PO₄) (Article No. 5357G)  in 1000ml of distilled water.

2) Dissolve 2.6 g of Field Stain A (Article No. 3854E) to the above solution.

3) Mix well in a warm water bath(Max 60^oC) and leave to stand at room temperature for 24 hours.

4) Filter the solution

Preparation of Field's Stain B Solution:

1) Dissolve 2.6 g of anhydrous disodium hydrogen phosphate(Na₂HPO₄) (Article No. 5974C)  and 2.6 g of potassium dihydrogen phosphate (KH₂PO₄) (Article No. 5357G)  in 1000ml of distilled water.

2) Dissolve 2 g of Field Stain B (Article No. 3854G) to the above solution.

3) Mix until dissolved

4) Filter the solution

Labeling and Storage:

Label properly both Field Stain A and Field Stain B to identify the contents.The label should display  information showing the name of the solution, date of preparation, prepared by, expiry date and storage condition information. In case the expiry date is not applicable then record the date the solution was first placed in the container.

The stains are stored at room temperature away from direct light and under these conditions the stains are stable indefinitely.