Standardized Heat Fixation for Blood Smears

Because a technique was needed for good fixation of blood smears without the use of solvents such as methanol, the effect of heat fixation on human and rat blood smears was studied. Slides were placed in a fused silica dish, covered by a Pyrex petri dish lid, and heated for 5 min in an oven at 150° C. After such fixation, smears stained by Giemsa' s solution showed that the blood elements retained their characteristic morphology. Thus, even though volatile substances may be lost and heat-labile constituents may be modified, this simple method avoids contact of the cells with solvents.