LABORATORY EVALUATION (Microscopic) Flashcards
Stain used to distinguish fungi in thick mucoid specimens or in samples that contain keratinous material such as skin, hair, and nails.
Potassium Hydroxide
Reagent used to preserve specimen in Potassium Hydroxide Method
0.1% thimerosal
Digestive capabilities can be enhanced with gentle heating or addition of
40% dimethyl sulfoxide
Nails in Potassium Hydroxide method require what percentage?
up to 25%
An alternative to KOH
10% or 25% NaOH with added glycerinq
Visualization of specimens in KOH may be enhanced with the use of:
lactophenol cotton blue (LCB) or calcofluor white (CW)
This is a nonspecific, non immunological fluorochromes that binds to β-1,3 and β-1,4 polysaccharides (Cellulose and chitin) of fungal cell walls and fluoresces when exposed to UV or blue-violet radiation
Calcofluor White
true/false
KOH (10%) is mixed in equal proportion with CW solution
true
true/false
After incubation of specimen in CW procedure, clearing and interaction of stain with the fungal elements occur
false
DURING incubation
true/false
Dematiaceous fungi may stain poorly with CW due to pigmentation that masks the fluorescence.
true
Fungal elements of specimens in CW stain:
Bluish white to Green
Color of background in CW
dark
What specimen displays “double-parentheses like” in CW
P. jirovecii
true/false
Cotton fibers fluoresce strongly and must be differentiated from fungal hyphae.
true
true/false
auramine-rhodamine stain is more rapid than CW
false
MALI! baliktad!
Stain applied to BAL fluid or CSF
Rapid Giemsa-like
what is specifically used in rapid giemsa-like?
Diff-Quik
Yeasts and trophozoites stain what color in rapid giemsa-like?
blue purple
What differentiates Leismania from Histoplasma?
Kinetoplast
Used in the detection of encapsulated microorganisms of C. neoformans in CSF.
Colloidal Carbon wet mounts
What is specifically used in colloidal carbon wet mounts?
India ink and nigrosin
true/false
In lactophenol cotton blue, the organism is refractory to the particles of ink, and capsules appear as clear halos around the
organism against a black background.
false
Colloidal carbon wet mount!
What is the color of the specimen’s capsule and its background in colloidal carbon wet mount?
clear halo and black background
true/false
In colloidal carbon wet mounts, the sensitivity is 97% followed by lateral flow assay (94%) and CALAS (74%)
true
Basic mounting medium for fungi
Lactophenol Cotton Blue
Commonly used for the microscopic examination of fungal cultures by tease or tape preparation.
Lactophenol Cotton Blue
What does lactophenol cotton blue consists of?
It consists of phenol, lactic acid, glycerol, and aniline (cotton) blue dye.
Clearing agent in LPCB?
lactic acid
killing agent in LPCB
phenol
Prevents drying in LPCB
Glycerol
Used for color in LPCB
Cotton blue
Analogous to cotton blue
Poirrier’s blue and aniline blue
Color of the specimen in LPCB
blue
what is mixed with LPCB to make an excellent permanent stain or fixative for mounting slide culture preparations..
10% polyvinyl alcohol
Stain used for the examination of bone marrow, buffy coat, and peripheral blood smears.
Giemsa stain
Stain used for the detection of intracellular yeast forms of H. capsulatum and fission yeast cells of Talaromyces marneffei
giemsa stain
stock Giemsa stain diluted with
1:10 phosphate buffered H2O
Color of cells in giemsa stain
Light to dark blue with hyaline halo
- Hyaline halo is due to poorly staining cell wall
Stain used for detection of bacteria and fungi
Gram Stain
Species that stains gram positive
Yeasts and pseudohyphae stain gram
species that stains gram negative
Hyphae (septate and coenocytic)
true/false
Cryptococcus spp. often have red amorphous material around yeasts.
false
orange duh!
Filaments of Nocardia stain at least partially acid-fast (pink or dark pink) in this stain
Modified acid fast
These species are negative in modified acid fast
Actinomyces and other actinomycete
Stain used for the detection of P. jirovecii in respiratory specimens such as lung biopsy specimen imprints and BAL specimens.
Toluidine blue
In toluidine blue, cyst walls of P. jirovecii stain
reddish blue or dark purple.
background color in toluidine blue
light blue background
true/false
trophozoites are often clumped and may be punched in, appearing crescent shaped. while cysts are not discernible.
false
baliktad! luh di nag-aaral
Stain used primarily to detect malignant cells. But it works well in sputum smears and good for differentiation of dimorphic fungi.
papanicolau
Background in papanicolau stain
green blue, orange to pink hues depending on the cell type.
It is a mucopolysaccharide stain that is not commonly used. The more commonly used one is mucicarmine stain
alcian blue
stain that is useful in visualizing the polysaccharide capsule of Cryptococcus.
alcian blue
Cryptococcus neoformans’ capsule stain what color
turquoise blue
In general, cryptococcus’ capsule stain what color
blue
What color is the background in alcian blue for histological sections of tissue?
pink
General purpose histologic stain.
Hematoxylin and Eosin (H&E)
stain that allows observation of natural pigments of fungi.
Hematoxylin and Eosin (H&E)
Best stain to demonstrate host tissue reaction and pigment of dematiaceous fungi.
Hematoxylin and Eosin (H&E)
Fungal cytoplasm and nuclei stain what color in H&E
pink; blue
what phenomenon is seen in basidiobolus and sporothrix that are stained with H&E?
splendore-hoeppli
What does periodic acid shiff stain?
glycogen
Color of fungi in PAS stain
pink to red purple
it demonstrated the double-contoured refractile walls in PAS stain
Blastomyces dermatitidis
Fungal stain of choice of many dermatopathologists
Periodic Acid Shiff
Pneumocystis jirovecii stain gray to black in what type of stain?
Gomori methenamine silver
background for gomori methenamine silver
green
true/false
gomori methenamine silver often stains fungi too shallow to observe structural details.
false
too DENSELY
This type of stain stains mucin
Mucicarmine
stain the cell walls of
Blastomyces dermatitidis and Rhinosporidium seeberi.
Mucicarmine
Useful for differentiating C. neoformans (gattii) from other fungi
mucicarmine
cryptococcus stain what color in mucicarmine?
pinkish red
Rhinosporidium seeberi stain what color in mucicarmine>
yellow
stain used for the detection of melanin of dematiaceous fungi and C. neoformans.
Fontana-Mason
C. neoformans’ cell walls appear as brown to black in this stain
Fontana-Mason
background color of fontana-mason
pale pink
true/false
It was originally thought to stain only dematiaceous fungi and C. neoformans (organisms that contain melanin), but it has now been shown to stain variably, but less intensely, A. fumigatus, A.. flavus, Trichosporon spp., Fusarium chlamydosporum, some Mucorales
true
Gram stain for bacteria; demonstrates the bacterial filaments of the actinomycetes, eg., Nocardia,
Actinomadura
Brown and Brenn
Specific method for detecting fungi in body fluids.
Fluorescent antibody stain
fluorescein-labeled Ab reacts with fungal antigen in the cell wall.
direct technique
unlabeled Ab complexes with fungal antigens. Fluorescein-labeled conjugate reacts with globulins attached to fungal antigens. Cell walls turn yellow-green.
indirect technique
Technique which is specific and highly sensitive, and can also be used to detect & measure antibodies.
immunoperoxidase technique
