BILIRUBIN Flashcards
What is bilirubin?
A breakdown product of the porphyrin ring of heme
How many fractions is bilirubin found in the blood?
2
What are the two fractions of bilirubin found in the blood?
Conjugated (B2) and Unconjugated (B1)
What is the alternative name for conjugated bilirubin?
Direct
What is the alternative name for unconjugated bilirubin?
Indirect
Who first described the reaction of bilirubin?
Ehrlich
What reagent was used in Ehrlich’s description of the bilirubin reaction?
Diazotized sulfanilic acid
What name was given to the type of reaction described by Ehrlich?
Diazo reaction
What color pigment was formed in the diazo reaction?
Red-blue
What did Van den Bergh find in 1913 regarding the diazo reaction?
It could be applied to serum samples with an accelerator or solubilizer
What is the chief purpose of neonatal bilirubin quantitation?
To monitor diseases causing jaundice in the newborn
What is another name for erythroblastosis fetalis?
Hemolytic disease of the newborn
What is a common cause of hemolytic disease of the newborn (HDN)?
Maternal alloimmunization to RhD
What is the average peak serum bilirubin concentration in a full-term newborn infant?
5 to 6 mg/dL
At what serum bilirubin concentration range is physiologic jaundice seen?
7 to 17 mg/dL
What term refers to the yellow staining of the basal ganglia due to severe jaundice?
Kernicterus
Which condition is NOT listed as a cause of neonatal jaundice?
Diabetes
Which type of bilirubin is water soluble?
Which type of bilirubin is found in urine?
Conjugated (Direct)
Which type of bilirubin has a high molecular weight?
Which type of bilirubin gives an indirect Van den Bergh reaction?
Unconjugated (Indirect)
Where is unconjugated (indirect) bilirubin normally found?
In plasma
What is unconjugated (indirect) bilirubin attached to non-covalently?
Albumin
Conjugated bilirubin is normally present in which location?
Bile
What is the Van den Bergh Reaction?
A reaction between bilirubin and Ehrlich diazo reagent
What is the color of the compound formed in the Van den Bergh Reaction?
Reddish purple
What type of bilirubin reacts directly with Ehrlich diazo reagent?
Conjugated bilirubin
What is conjugated bilirubin also known as?
Direct bilirubin
When does unconjugated bilirubin react with Ehrlich diazo reagent?
After the addition of methyl alcohol
What is unconjugated bilirubin also known as?
Indirect bilirubin
Wahlefeld et al.
Detergent as accelerator
What is the purpose of using a detergent in the Wahlefeld method?
To accelerate the reaction and avoid protein precipitation
Under what conditions does DPD react with bilirubin?
Acidic
What is the main component that DPD reacts with in the Wahlefeld method?
Bilirubin
Van den Bergh
Serum
What is the pH range of the acidic medium used in coupling total bilirubin with a diazonium salt?
1-2
Which compound is coupled with total bilirubin in the Wahlefeld Method?
Diazonium salt (DPD)
What is the main product formed when total bilirubin reacts with DPD?
Azobilirubin
Malloy & Evelyn
50% methanol
Within how many hours should samples kept at room temperature be analyzed?
Two hours
How long can bilirubin in serum remain stable when stored frozen at -20°C?
Three months
What is the effect of direct sunlight on bilirubin levels in the serum within one hour?
Decrease up to 50%
Up to what concentration of serum triglycerides is considered non-interfering?
1000 mg/dl
Which of the following is a mechanism of unconjugated hyperbilirubinemia?
Increased bilirubin production
What can cause decreased liver uptake in relation to unconjugated hyperbilirubinemia?
Decreased liver uptake
Which mechanism involves the liver’s inability to properly process bilirubin resulting in unconjugated hyperbilirubinemia?
Decreased liver conjugation
Decreased liver uptake results in:
Retention of unconjugated bilirubin
What is the normal range for adults and infants older than 1 month?
0.2-1.0 mg/dl
What is the expected blood content range for a full term newborn up to 24 hours?
2.0-6.0 mg/dl
What are the expected blood values for infants up to 48 hours?
6.0-10.0 mg/dl
What is the expected range of blood content in infants from 3 to 5 days?
4.0-8.0 mg/dl
MAMA MO
