Which marker best reflects hepatic synthetic function?

• A. Albumin
• B. Ammonia
• C. Bilirubin
• D. AST

Answer: (A)

The main concept is how the liver’s ability to produce proteins reflects its synthetic function. Albumin is the most abundant plasma protein made by the liver and is essential for maintaining oncotic pressure and transporting many substances. Because its production directly depends on intact hepatic synthetic capacity, serum albumin levels closely reflect how well the liver can synthesize proteins. When synthesis drops, albumin falls, producing edema and reduced transport functions—hallmarks of impaired synthetic function.

Ammonia, on the other hand, relates to the liver’s detoxification via the urea cycle; high levels signal impaired clearance rather than reduced protein production. Bilirubin processing involves uptake, conjugation, and excretion into bile, so elevations point to excretory or cholestatic issues rather than synthetic capacity. AST is an enzyme released from damaged hepatocytes, indicating injury to liver cells rather than how much protein the liver can synthesize.

So, albumin best reflects hepatic synthetic function.