(M) Week 9: Screening test for unstable hemoglobin Flashcards
Which screening test is this for unstable hemoglobin:
The red blood cell hemolysate prepared from a blood specimen suspected with unstable
hemoglobin is incubated with 15% or 17% isopropanol and incubated at 37 OC
isopropanol precipitation test
what percent of isopropanol is utilized in the isopropanol precipitation test
15-17%
what do we check for in the mixture after 5 mins and 10 mins in the isopropanol precipitation test
precipitation / flocculation
unstable hgb shows a (faster/slower) rate of precipitation
faster
For isopropanol precipitation test
why do unstable hemoglobin precipitate faster?
their bonds are easily weakened by isopropanol
normal hemoglobin start to precipitate at _______ minutes during the isopropanol precipitation test
45 minutes
40
Which screening test is this for unstable hemoglobin:
The hemolysate prepared mixed with tris buffer solution with a pH of 7.4 is incubated at 50 deg C
for 2 hours and another duplicate sample is incubated at refrigerated temperature
heat denaturation test
in heat denaturation test, unstable hemoglobin will precipitate easily at (high/low) temperature
high
what is used to measure the absorbance of hemoglobin concentration of the supernatant of both the heated and refrigerated mixture using the cyanmethemoglobin method
spectrophotometric analysis
what is the formula for the concentration of unstable Hgb
%unstable Hgb = (absorbance of refrigerated - absorbance of heated / absorbance of refrigerated) 100
what are used to confirm the high level of unstable Hgb test in heat denaturation test
isopropanol precipitation test
RBC with unstable hgb will form _______ after the cells are incubated with acetylphenylhydrazine
heinz inclusion bodies
What is the stain used for the Heinz bodies inclusion test
crystal violet
G6PD DEFICIENCY
red cells with faulty reducing systems will show more than _____ of red cells with 5 or more inclusions
32%
G6PD DEFICIENCY
normal red cells will show less than ___ of red cells with 5 or more inclusions
32%
Heinz bodies are common in these enzymopathies:
G-6-PD deficiency
glutathione peroxidase dificiency
triophosphate isomerase deficiency
Where is the presence of Hgb H observed?
alpha-thalassemia major
a condition where three alpha genes are absent or deleted caused by the excessive production of the beta globin chain in the cytoplasm of the red cells
alpha-thalassemia major
what is the cause of alpha-thalassemia major
excessive production of the beta globin chain
why is hemolytic anemia observed in alpha-thalassemia major?
excessive beta-globin chain => disfigured red cells => rapid removal by macrophages
How do we increase the yield of positive detection of Hgb H in cases where patient is suspected with homozygous alpha thalassemia?
blood is incubated with 1% brilliant cresyl blue (oxidizing agent)
what color would the Hgb H / excessive beta globin chains be in microscopic analysis?
multiple, evenly distributed bluish green colored bodies
what pattern is observed in red cells in the microscopic determination in the Hgb H preparation and staining?
golf ball pattern
reticulocyte inclusions are also stained by brilliant cresyl blue but shows what color
blue to purple
