SAF fixative is a fixative made by mixing sodium acetate， acetic acid， and formalin (an aqueous solution of formaldehyde) in a certain proportion. Formaldehyde， as a representative aldehyde fixative， has extremely strong permeability and good fixation effect; Sodium acetate and acetic acid help to adjust the pH value of the solution， thereby optimizing the fixation effect.

SAF fixative is mainly used to immobilize intestinal parasitic pathogens such as nematodes， flukes， tapeworms， and protozoa. In addition， it can also be used for pathogen detection of gastrointestinal worm infections， protozoan infections， as well as schistosomiasis， clonorchiasis， and pulmonary fluke infections. In the laboratory， SAF fixative is commonly used to preserve parasite eggs and protozoan cysts in fecal specimens for subsequent detection and analysis.