In evaluating a pattern suggestive of cholestasis, which statement best distinguishes the bone versus liver source?

In evaluating a pattern suggestive of cholestasis, which statement best distinguishes the bone versus liver source?

• A. Bone disease is suggested by ALP elevation with normal GGT; cholestasis is suggested by both ALP and GGT elevation
• B. Bone disease is suggested by ALP elevation with elevated GGT; cholestasis is suggested by normal ALP and GGT
• C. Bone disease shows elevated CK; cholestasis shows elevated ALT
• D. Bone disease shows elevated ALT; cholestasis shows elevated CK

Answer: (A)

The main idea is using ALP and GGT to tell whether elevated ALP comes from bone or liver. ALP is produced by both bone and liver, so an isolated rise doesn’t tell you the source. GGT, on the other hand, is much more specific to the liver. When ALP is high but GGT is normal, the most likely source is bone, such as in bone growth or turnover. When both ALP and GGT are elevated, that pattern points to a liver/biliary origin, as seen in cholestasis. So the statement that bone disease shows ALP elevation with a normal GGT, while cholestasis shows elevation of both ALP and GGT, best distinguishes between the two sources.

The main idea is using ALP and GGT to tell whether elevated ALP comes from bone or liver. ALP is produced by both bone and liver, so an isolated rise doesn’t tell you the source. GGT, on the other hand, is much more specific to the liver. When ALP is high but GGT is normal, the most likely source is bone, such as in bone growth or turnover. When both ALP and GGT are elevated, that pattern points to a liver/biliary origin, as seen in cholestasis.

So the statement that bone disease shows ALP elevation with a normal GGT, while cholestasis shows elevation of both ALP and GGT, best distinguishes between the two sources.