Diff-Quick

Diff-Quik is a commercial Romanowsky stain variant, commonly used in histological staining to rapidly stain and differentiate a variety of smears, commonly blood and non-gynecological smears, including those of fine needle aspirates. It is based on a modification of the Wright Giemsa stain pioneered by Bernard Witlin in 1970. It has advantages over the older Wright Giemsa staining technique, as it reduces the 4 minute process into a simplified 15 second operation, and allows for selective increased eosinophilic or basophilic staining depending upon the time the smear is left in the staining solutions.

Diff-Quik is utilized on material which is air-dried prior to alcohol fixation (rather than immersed immediately ie. "wet-fixed").

The primary use of Romanovsky-type stains is for cytoplasmic detail, such as intracytoplasmic mucins, fat droplets and neurosecretory granules. Extracellular substances, such as free mucin, colloid, ground substance, etc, are also easily stained, and appear metachromatic. Microbiologic agents, such as bacteria and fungi, also appear easier in Diff-Quik.

Components

The Diff-Quik stain consists of 3 solutions:

• Diff-Quik fixative reagent
  • Triarylmethane dye
  • Methanol
• Diff-Quik solution I (eosinophilic)
  • Xanthene dye
  • pH buffer
  • Sodium azide
• Diff-Quik solution II (basophilic)
  • Thiazine dye
  • pH buffer

Results

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	Blue

Alternatives

• Papanicolaou stain
• Wright Giemsa stain
• Romanowsky staining