FIELD’S STAIN SOLUTION B

Field’s Stain Solution B is a stain for microscopic examination of blood films. It is commonly used along with Field’s Stain A for differential staining of spirochaetes, protozoa, and other blood-borne organisms. The staining method also supports screening of thick blood films for malarial parasites.
The field’s stain contains methylene blue and eosin. The mixture of basic and acidic dyes results in differential staining. These dyes bind to different cell components and give different colours. Acidic components such as the nuclear material, absorb the blue to purple shades of the basic dye. Basic components, including parts of the cytoplasm, react with the acidic dye and show eosinophilic or acidophilic staining. Both dyes can be taken up by neutral components.
The solution has a clear yellow-orange appearance and meets the above sensitivity criteria. For accurate detection of malaria, blood smears should be made soon after blood collection, ideally within 3-4 hours. Methanol used for fixation should be completely water-free, as moisture can affect staining results. Slides need to be cleaned as well, to get rid of any detergent residues. In thick films, excess stain residue or lysed red blood cell material may interfere with the microscopic examination.

Used with Field’s Stain A for differential staining of blood films, supporting the visualization of spirochaetes, protozoa, and malarial parasites.