MLT GlobeChemistry: Liver function & bilirubin – page 5
84 Chemistry MCQs on Liver function & bilirubin with answers and explanations.
A day after cardiac arrest and resuscitation, a patient has ALT 3000 U/L, AST 4000 U/L and LD 6000 U/L. The values fall by half within 2–3 days. The most likely diagnosis is:
Hypoperfusion causes rapid centrilobular necrosis with very high aminotransferases, a very high LD (ALT/LD ratio often below 1.5) and a quick fall. Viral hepatitis rises and falls more slowly with lower LD.
ALT is 400 U/L (upper limit 40) and ALP is 240 U/L (upper limit 120). Using R = (ALT ÷ ALT ULN) ÷ (ALP ÷ ALP ULN), the liver injury pattern is:
ALT is 10 × ULN and ALP is 2 × ULN, so R = 10 ÷ 2 = 5, a hepatocellular pattern. The R ratio is widely used to classify drug-induced liver injury.
An infant with prolonged conjugated jaundice has a very faint alpha-1 band on electrophoresis. Liver biopsy shows PAS-positive, diastase-resistant globules in hepatocytes. The most likely genotype is:
The Z variant of alpha-1 antitrypsin misfolds and is trapped in hepatocytes, causing neonatal cholestasis and low serum levels. PiMM is normal; PiMS and PiSS give only mild reductions.
In the Jendrassik–Grof method, alkaline tartrate is added at the end of the reaction to:
Alkaline tartrate shifts azobilirubin to a blue color with maximum near 600 nm, away from hemoglobin and carotene interference. Ascorbic acid is the reagent that destroys excess diazo reagent.