LFTs elevated alone may indicate bone disease, pregnancy, or hyperparathyroidism. Which enzyme is elevated in this scenario?

LFTs elevated alone may indicate bone disease, pregnancy, or hyperparathyroidism. Which enzyme is elevated in this scenario?

• A. ALT
• B. AST
• C. ALP
• D. LDH

Answer: (C)

Alkaline phosphatase is the enzyme that rises in conditions with increased bone formation or placental activity. In bone disease, osteoblasts are highly active to lay down new bone, boosting ALP levels. In pregnancy, placental production of ALP adds to the serum level. In hyperparathyroidism, there is increased bone turnover and remodeling, which also raises ALP. The other enzymes—ALT and AST come from hepatocytes and typically rise with liver injury, while LDH is a nonspecific marker of tissue breakdown. So when LFTs are elevated in isolation, ALP is the most likely enzyme to be elevated. If needed, checking GGT can help differentiate whether the source is liver/biliary (GGT elevates) or bone/placental (GGT normal).

Alkaline phosphatase is the enzyme that rises in conditions with increased bone formation or placental activity. In bone disease, osteoblasts are highly active to lay down new bone, boosting ALP levels. In pregnancy, placental production of ALP adds to the serum level. In hyperparathyroidism, there is increased bone turnover and remodeling, which also raises ALP. The other enzymes—ALT and AST come from hepatocytes and typically rise with liver injury, while LDH is a nonspecific marker of tissue breakdown. So when LFTs are elevated in isolation, ALP is the most likely enzyme to be elevated. If needed, checking GGT can help differentiate whether the source is liver/biliary (GGT elevates) or bone/placental (GGT normal).