Manual Test Methods Flashcards
What are characteristics of a good smear
smoot even film with feathered ends
minimum of 3cm in length
blood should not spill over the end or sides
What causes a smear to be too short
spreading the blood too quickly, angle of spreading slide greater than 30 degrees
What causes a smear to be too long
spreading the blood too slowly, angle of spreader is less than 30 degrees
What causes a smear to be too thin
drop of blood too small, patient has low HGB
What causes a smear to be too thick
drop of blood too large, patient abnormalities with viscous blood
What causes chattering or streaking in a smear
clots/clumps/debris on slide, blood drying out, glass edge not smooth
What does malaria protocol need
4 thin smears (2 stained, 2 unstained) and 4 thick smears
When is a buffy coat smear made
when the white blood cell count is too low for analysis on a routine smear or when bacteria/parasites are present
What is a buffy coat smear used for
to evaluate WBC morphology
When is a cytospin smear used
whenever a fluid has a WBC count above 5x10^6/L
What types of smears are used for bone marrows
push smears, squash smears and touch-prep smears
What are the components of a wright-giemsa stain
methylene blue, purified azure blue B, eosin
What fixative is used for the wright-giemsa stain
methanol
What is the pH of the wright-giemsa stain
6.8
What components are stained by the methylene blue and azure B in wright-giemsa
nucleic acids, RNA, DNA, neutrophil granules
What components are stained by the eosin in wright-giemsa
hemoglobin, eosinophil, neutrophil granules
What are the components of a May-Grunwald stain
eosin, methylene blue
What is the pH of a may-grunwald-giemsa stain
6.8
What does the May-grunwald component of the may-grunwald-giemsa stain
cytoplasm
What does the giemsa component of the may-grunwald-giemsa stain
nuclear and inclusions
What are the components of giemsa stain for malaria
eosin, purified azure B, methylene blue
What are common supervital stains
new methylene blue, brilliant cresyl blue, methyl violet, crystal violet, brilliant green
What is the principle of supervital stains
used to stain living and unfixed cells in vitro to demonstrate heinz bodies and reticulocytes
What are the components of the prussian blue iron stain
0.2N HCl, Potassium ferrocyanide
What is the principle of the prussian blue iron stain
HCl splits ferric iron from hemosiderin and then the iron combines with potassium ferricyanide to form a blue complex
What are considerations when viewing an iron stain slide
iron must be inside cells, extracellular iron is considered artifact
What can cause increased iron stores
megaloblastic anemia, hemolytic anemia, sideroblastic anemia, anemia of chronic disease, lead poisoning, hemosiderosis
What can cause decreased iron stores
iron deficiency anemia, polycythemia vera
What is myeloperoxidase stain used for
stains primary granules in monocytes and myeloid lineage
What is sudan black stain used for
stains primary and secondary myeloid granule lipids, weakly stains granules in monocytes
What is periodic acd-schiff stain used for
stains glycogen compounds commonly found in lymphoid lineage cells
What is non-specific esterase stain used for
stains non-specific esterase compounds in monocytes
What is the Leukocyte Alkaline Phosphatase stain used for
cells are scored based on intensity of staining, higher intensity is seen in mature neutrophils or band cells
What causes increased LAP scores
leukemoid reaction, multiple myeloma, hodgkins disease, myeloproliferative disorders, aplastic anemia
What causes decreased LAP scores
chronic myelogenous leukemia, paroxysmal nocturnal hemoglobinuria. sickle cell anemia, myelodysplastic syndromes
How does high pH effect staining
increased dissociation of methylene blue cause dark blue colour
RBC stain green/blue
neutrophils can appear toxic
How does low pH effect staining
increased dissociation of eosin causing dark pink colour
RBC stain red/orange
WBC nuclei will be pale
eosin granules will be bright orange
How does short stain time effect staining
pale slides
How does long staining time effect staining
dark/overstained slides
What are common artifacts in slides
debris, stain precipitate, water, thick smears, no blood smear left
What is done under the 10x objective during smear analysis
check cell distribution and stain
WBC estimate
smear scan for rouleaux, smudge cells, fibrin strands, platelet clumps, large/abnormal cells, parasites
What is done under the 50x objective during smear analysis
WBC differential and morphologies
Overview of RBC morph
What is done under the 100x objective during smear analysis
PLT estimate and morphology
RBC morphology
What is the calculation for % parasitemia or %retic
(square A/Square B) x (100/9)
What is the calculation for corrected WBC
WBC count/(1+(nRBC/100))
How many cells should be counted using a miller-occular
111 cells in square B
What does transudate mean
an accumulation of fluid caused by a non-inflammatory circulation disturbance
What are examples of disorders tha cause transudates
congestive heart failure, liver disease, renal disease, obstructive tumors
What does exudate mean
an accumulation of fluid caused by an inflammatory condition
What is done to a fluid once it is recieved in the lab
gross examination, WBC count, RBC count if requested, cytospin differential if indicated, crystals if requested
What is done to a CSF once it is recieved in the lab
gross examination, cell count, cytospin differential if indicated
What can cause cloudy and colourless CSF
high WBC count, presence of microorganisms
What can cause coloured CSF
hemoglobin/RBC, increased proteins, bilirubin
What is an ESR
a nonspecific test used as a marker for tissue damage or inflammation
What causes increased ESRs
infection, rheumatoid arthritis, TB, cancer
What is the principle of the ESR
when more acute phase reactants are present the zeta potenetial is reduced and RBC fall quicker than normal
What can cause falsely increased ESR testing
increased rouleaux formation, decreased numbers of red cells, macrocytes, increased albumin
What can cause falsely decreased ESR testing
abnormally shaped red cells, increased numbers of red/white cells, microcytes, increased fibrinogen, increased immunoglobulin
