Diff-Quik is a commercial Romanowsky stain variant used to rapidly stain and differentiate a variety of pathology specimens. It is most frequently used for blood films and cytopathological smears, including fine needle aspirates. The Diff-Quik procedure is based on a modification of the Wright-Giemsa stain pioneered by Harleco in the 1970s, and has advantages over the routine Wright-Giemsa staining technique in that it reduces the 4-minute process into a much shorter operation and allows for selective increased eosinophilic or basophilic staining depending upon the time the smear is left in the staining solutions.
Diff-Quik may be utilized on material which is air-dried prior to alcohol fixation rather than immersed immediately (i.e. "wet-fixed"), although immediate alcohol fixation results in improved microscopic detail.
The primary use of Romanowsky-type stains in cytopathology is for cytoplasmic detail, while Papanicolaou stain is used for nuclear detail. Diff-Quik stain highlights cytoplasmic elements such as mucins, fat droplets and neurosecretory granules. Extracellular substances, such as free mucin, colloid, and ground substance, are also easily stained, and appear metachromatic. Microbiologic agents, such as bacteria and fungi, also appear more easily in Diff-Quik. The stain can be used to detect Helicobacter pylori, and it may also be used in the evaluation of sperm morphology.
Due to its short staining time, Diff-Quik stain is often used for initial screening of cytopathology specimens. This staining technique allows the cytotechnologist or pathologist to quickly assess the adequacy of the specimen, identify possible neoplastic or inflammatory changes, and decide whether or not additional staining is required.
The Diff-Quik stain consists of 3 solutions:
|Neutrophils||Blue nucleus, pink cytoplasm, violet granules|
|Eosinophils||Blue nucleus, blue cytoplasm, red granules|
|Basophils||Purple/dark blue nucleus, violet granules|
|Monocyte||Violet nucleus, light blue cytoplasm|
|Bacteria and fungi||Dark blue|
|Cytoplasm, collagen and muscle||Various shades of pink, orange, yellow and blue|
|Spermatozoa||Light blue acrosomal region, dark blue post-acrosomal region|