Diff-Quik is a commercialRomanowsky stain variant used to rapidly stain and differentiate a variety ofpathology specimens. It is most frequently used forblood films andcytopathological smears, includingfine needle aspirates.[1][2][3] The Diff-Quik procedure is based on a modification of theWright-Giemsa stain pioneered by Harleco in the 1970s,[1] 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.[4]
There are generic brands of such stain,[1][5] and the trade name is sometimes used loosely to refer to any such stain (much as "Coke" or "Band-Aid" are sometimes used imprecisely).
Diff-Quik may be utilized on material which isair-dried prior to alcoholfixation rather than immersed immediately (i.e. "wet-fixed"), although immediate alcohol fixation results in improved microscopic detail.[2][3][6]
The primary use of Romanowsky-type stains in cytopathology is forcytoplasmic detail, whilePapanicolaou stain is used for nuclear detail. Diff-Quik stain highlights cytoplasmic elements such asmucins, fat droplets and neurosecretory granules. Extracellular substances, such as free mucin, colloid, andground substance, are also easily stained, and appearmetachromatic. Major applications includeblood smears,bone marrow aspirates,semen analysis and cytology of variousbody fluids includingurine andcerebrospinal fluid.[7][8] Microbiologic agents, such as bacteria and fungi, also appear more easily in Diff-Quik.[3] This is useful for the detection of for exampleHelicobacter pylori from gastric and pyloric specimens.[5]
Due to its short staining time, Diff-Quik stain is often used for initial screening of cytopathology specimens. This staining technique allows thecytotechnologist orpathologist to quickly assess the adequacy of the specimen, identify possibleneoplastic or inflammatory changes, and decide whether or not additional staining is required.[4][9][10]
The Diff-Quik stain consists of 3 solutions:[4]
| Structure | Colour |
|---|---|
| Erythrocytes | Pink/yellowish red |
| Platelets | Violet/purple granules |
| 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 andfungi | Dark blue |
| Cytoplasm,collagen andmuscle | Various shades of pink, orange, yellow and blue[11] |
| Spermatozoa | Light blueacrosomal region, dark blue post-acrosomal region[8] |