Also referred to as alanine aminotransferase or even serum glutamate-pyruvate transaminase (GPT), the first thing to know is that alanine transaminase (ALT) is an enzyme primarily found in the liver, but also present in smaller amounts in the plasma, kidneys, heart, and other muscles. It is necessary for converting alanine into pyruvate as part of the Cahill cycle of cellular energy production.
The second thing to know is that when liver cells are damaged, they release ALT into the blood and thus can indicate liver damage or inflammation. This allows liver function panels and comprehensive metabolic panels to help diagnose and monitor liver conditions. However, many things affect blood ALT levels, including (but not limited to) biological sex, age, BMI, prescriptions, diet, and exercise. In addition, different labs use different normal ranges, so it is beyond the abilities of most lay people to diagnose themselves, thus depending on medical professionals for that task. And, to be honest, its ratio to aspartate transaminase is probably more important.
For reference here are the ALT/SGPT levels from my CMPs that are on record:
January 17, 2025 - 46 U/L
Normal range for this lab is 16 - 63.
December 24, 2024 - 22 U/L
Normal range for this lab is 10 - 49.
Additional results from the same lab*:
23 U/L 12/23/2024 3:54 am Normal
12 U/L 12/22/2024 4:20 am Normal
11 U/L 12/21/2024 4:10 am Normal
8 U/L 12/19/2024 3:36 pm Low
24 U/L 05/04/2024 2:02 am Normal
Whereas high levels can indicate liver damage, lower-than-normal ALT levels could indicate a vitamin B6 deficiency or chronic kidney disease, amongst other things.
*Let's hear it for digital medical records! Now, if only hacking them and changing the values improved one's health…
288 words for BQ 2025