Stains

Question 1

Giemsa stain

Answer 1

Chlamydia, Borrelia, Rickettsiae, Trypanosomes, Plasmodium (malaria)

Question 2

Periodic acid-Schiff stain (PAS)

Answer 2

Stains glycogen, mucopolysaccharides

Used to diagnose Whipple disease (Tropheryma whipplei)

Also stains unsecreted A1AT in hepatocytes in A1AT deficiency

Question 3

Ziehl-Neelsen (carbolfuchsin)

Answer 3

Stains acid-fact organisms (Nocardia, Mycobacterium)

High lipid content in Mycobacteria cell wall detected by carbolfuchsin

Question 4

Fluorescent antibody staining and dark-field microscopy

Answer 4

Treponema

Question 5

India ink stain

Answer 5

Cryptococcus neoformans (mucicarmine can also be used to stain thick polysaccharide capsule red)

Question 6

Silver stain

Answer 6

Fungi (e.g. Pneumocystis), Legionella, H. Pylori, Borrelia

Question 7

Prussian blue stain

Answer 7

Distinguishes iron (blue) from lipofuscin in hepatocytes

Hemochromatosis; Sideroblastic anemia

Question 8

GFAP

Answer 8

Intermediate filament of neuroglia (astrocytes, oligodendrocytes, ependymal cells)

Question 9

Nissl substance

Answer 9

Cell bodies and dendrites of neurons (stains RER)

Question 10

Keratin

Answer 10

Intermediate filament of epithelial cells

Question 11

Desmin

Answer 11

Intermediate filaments of muscle cells (e.g. rhabdomyosarcoma)

Question 12

Gomori trichrome stain

Answer 12

Blotchy red muscle fibers reveal mitochrondral myopathies

Question 13

Mucicarmine

Answer 13

Cryptococcus neoformans

Question 14

Vimentin

Answer 14

Intermediate filament of mesenchyme

Question 15

Neurofilament

Answer 15

Intermediate filament of neurons

Question 16

Chromogranin

Answer 16

Neuroendocrine cells (small cell carcinoma of the lung, carcinoid tumors)

Question 17

S-100

Answer 17

Melanoma, Schwannoma, and Langerhans cell histiocytosis