Heffner Criteria (Pleural Exudate, No Serum Sample)
The Heffner criteria, also called the abbreviated Light's criteria, classify a pleural effusion as exudative without a paired serum sample.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Pleural fluid LDH
- 50 U/L
- THE LABORATORY'S upper limit of normal for SERUM LDH
- 250 U/L
- Pleural fluid cholesterol
- 20 mg/dL
- Pleural fluid protein
- 3.5 g/dL
Result: Exudate
The tool opens with these values already filled in. Replace them with your own.
What the result means
- LDH
- Pleural fluid LDH above 0.45 x THE LABORATORY upper limit of normal for SERUM LDH. NOT a fixed number - it varies by lab.
- Cholesterol
- Pleural fluid cholesterol above 45 mg/dL. Pleural fluid only.
- Protein
- Pleural fluid protein above 2.9 g/dL - NOT 3.0. This is the test the two-test rule drops.
- Two rules
- THREE-test and TWO-test (LDH or cholesterol) rules both exist. They disagree exactly when protein is the only positive.
- Not serum-free
- The LDH test needs the lab reference value. No patient blood is drawn, but a cutoff must never be hard-coded.
- Trade
- About 98.4% sensitive, 85% specific. Far less specific than Light’s. A positive here is WEAKER evidence of an exudate.
- Diuretics
- Shared failure mode: diuresis concentrates a transudate and can push either rule to a false exudate.
- Scope
- Classifies only. Does NOT give the cause, does not indicate or contraindicate drainage.
What you enter
- Pleural fluid LDH.
- THE LABORATORY'S upper limit of normal for SERUM LDH - a reference value, not the patient's blood.
- Pleural fluid cholesterol.
- Pleural fluid protein.
Full field descriptions
- THE LABORATORY'S upper limit of normal for SERUM LDH - a reference value, not the patient's blood. REQUIRED AND NOT DEFAULTED: the cutoff is 0.45 times this, and it differs between laboratories and assays.
- Pleural fluid cholesterol. Exudate above 45 mg/dL.
- Pleural fluid protein. Exudate above 2.9 g/dL - NOT 3.0. This is the test the two-test rule drops.
How this is calculated
- Rule
- ANY ONE of three tests = EXUDATE. The tests do not vote; two negatives do not outweigh one positive.
Heffner JE, Brown LK, Barbieri CA. Diagnostic value of tests that discriminate between exudative and transudative pleural effusions. Chest. 1997;111(4):970-980, with the abbreviated cut points reported by Heffner JE and colleagues (Chest 2002). Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.