1.        Deparaffinize and hydrate to distilled water.

2.        Place in ammonium hydroxide – alcohol for 5-10 minutes.  This is prepared by adding 10 ml of concentrated ammonium hydroxide to 90 ml of 95% alcohol.

3.        Wash well in running tap water and rinse in distilled water.

4.        Stain with 0.1% nuclear fast red for 5 minutes unless otherwise specified.

Formalin pigment is also called acid formaldehyde hematein.  It may be present in blood-containing tissue, especially if fixation is delayed or if non-buffered formalin is used.  It appears as a brown-black deposit in and around blood vessels or where erythrocytes are present.  It is birefringent and can be polarized.

Malaria pigment (hemozoin) is found in malarial parasites and may be seen in the liver, spleen, bone marrow, lymph nodes, and brain cappillaries. It is similar to formalin pigment in every respect, and can be differentiated from formalin pigment only by its location and distribution.

Culling, C.F.A.:  Handbook of Histopathological and Histochemical Methods, 3rd Ed., London, Butterworths, 1974, pp. 377, 379, 384-385.

Lillie, R.D. and Fullmer, H.M.:  Histopathologic Technic and Practical Histochemistry, 4th Ed., McGraw-Hill, New York, 1976, pp. 488-489.

Luna, L.G.:  Manual of Histologic Staining Methods of the Armed Forces Institute of Pathology, 3rd Ed., New York, McGraw-Hill, 1968, p. 43.