I've never been told my liver function results along with my cholesterol numbers before today. But now I will always ask for them. Why? Because I don't know what levels my liver normally functions at.
Today I received a call to let me know that while on Simvastatin and enjoying a meatless diet for three months, my cholesterol numbers did not change significantly. However, my liver numbers were elevated.
What the heck does that mean? I wanted to know. The nurse told me my AST was at 43, and it should be between 14 and 34. My ALT was 75, and it should be between 1 and 33.
Oh. Of course. I see.
But I did not see at all. Although I tried to gain more of an explanation, there wasn't much more she could tell me, and perhaps she had a million more phone calls to make about results more dire than mine. So after I hung up, I decided to do a little investigating of my own, because that's what I do when I don't understand something.
I will now enlighten you. Let me first explain that the blood test you receive to determine cholesterol levels while on a statin drug is also used to determine the presence of particular liver enzymes in the blood. When your liver becomes injured, these enzymes spill into the blood stream. Therefore they can be read by a simple blood test.
Here's some terminology for you along with pertinent information: AST stands for aspartate amniotransferase. It is also known as serum glutamic oxaloacetic tranaminase, or GSOT for short. The test for AST is not a specific indicator of liver injury. This is because injury to the heart, muscle, kidney and the brain may also have elevated AST numbers.
ALT stands for alanine amniotranferase. It's also known as serum glutamic pyruvic transaminase, or SGPT for short. Thank goodness for acronyms. The test for ALT is a more specific indicator of liver damage.
My doctor's office gave me a different AST and ALT "normal range" than could be found on any of the sites I visited. MedecineNet.com informed me the AST normal range fell between 5 and 40 units per liter of serum. (Serum is the liquid part of the blood.) Liverdoctor.com mentioned 0-45, and SimpleFactsProject listed it as 5-43. Likewise, the ALT numbers were: 7-59 per liter of serum, 0-45 and 5-60 respectively.
Okay, that was confusing. So I'll stick to my doctor's office's numbers. AST: between 14 and 34. ALT: between 1 and 33.
Now, here is something interesting I found on MedecineNet.com. Taking particular medications may cause liver enzymes in the bloodstream to rise. In a study using my favored pain reliever of choice, Tylenol, 33-44% of the people who took 4g. of it daily for 2 weeks had elevated ALT levels: up to three times the normal limit. The people taking the placebo drug had no change.
Other medications that may increase liver enzyme levels include ibuprofin, atorvistatin (Lipitor), niacin, fluconazole (anti-fungal mediaction) and many others. For a full list see: http://www.medicinenet.com/liver_blood_tests/page3.htm.
It's also important to stress that moderate liver enzyme elevation is entirely normal. But I want to point out my doctor became nervous seeing my numbers which, in my medical-naive opinion, do not seem extremely high. I wish I'd kept track of my liver function numbers before this came about, but I never thought to do so. But I will.
And so should you.