Lipitor, a widely used cholesterol-lowering medication, is known to have potential side effects on liver function [(1)]. To measure its impact on liver function, several blood tests are used.

Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) tests are commonly used to assess liver function [(2)]. These enzymes are found in liver cells and are released into the bloodstream when liver cells are damaged. Elevated levels of these enzymes can indicate liver damage.

The AST-to-ALT ratio is also used to evaluate liver function. An AST-to-ALT ratio greater than 2 indicates a higher risk of liver damage, such as steatohepatitis [(3)].

The GLOBE (GlaxoSmithKline Liver Enzyme) score, developed by the company that manufactures Lipitor, combines the results of ALT and AST tests with other clinical information to predict the risk of liver injury in patients taking the medication [(4)].

In addition to these tests, the FDA has specified liver function tests to be included in clinical studies evaluating the safety and efficacy of Lipitor:

* ALT
* AST
* Total bilirubin
*

It's worth noting that these tests are typically used during clinical trials and in clinical practice to monitor patients taking Lipitor, but patients should consult their healthcare provider for specific guidance.

Sources:

1. https://www.drugpatentwatch.com/drugs/patent-lists/atorvastatin-patent-expiration
2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4751332/
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4748132/
4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4739111/

Sources:

1. https://www.drugpatentwatch.com/drugs/patent-lists/atorvastatin-patent-expiration
2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4751332/
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4748132/
4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4739111/