Hy's Law (drug-induced liver injury)
Checks a liver-injury lab set against Hy's Law.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- ALT
- 250 U/L
- ALT upper limit of normal
- 40 U/L
- Total bilirubin
- 3.5 mg/dL
- Total bilirubin upper limit of normal
- 1.2 mg/dL
- Alkaline phosphatase
- 150 U/L
- Alkaline phosphatase upper limit of normal
- 120 U/L
Result: a potential case, because other causes are not recorded as ruled out
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Criterion 1
- An aminotransferase, ALT or AST, at or above 3 times its upper limit of normal.
- Criterion 2
- A total bilirubin above 2 times its upper limit of normal.
- Criterion 3
- No cholestasis at the outset, taken as an alkaline phosphatase below 2 times its upper limit of normal.
- Criterion 4
- No other reason for the combination: viral hepatitis A, B, C and E, other liver disease, and any other drug capable of the same injury are ruled out.
- Labs only
- The first three make a potential case. The fourth is a judgment, not a measurement, and it is what turns a potential case into a case.
- What it is for
- A signal about a drug rather than a prognosis for a patient. Such cases in trials predict severe injury at a rate in the wider population.
What you enter
- ALT
- ALT upper limit of normal
- AST, if higher than the ALT
- AST upper limit of normal
- Total bilirubin
- Total bilirubin upper limit of normal
- Alkaline phosphatase
- Alkaline phosphatase upper limit of normal
- Other causes ruled out: viral hepatitis A, B, C and E, other liver disease, and any other drug capable of the same injury
How this is calculated
US Food and Drug Administration. Guidance for Industry -- Drug-Induced Liver Injury: Premarketing Clinical Evaluation. July 2009. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.