Feature Tennessee Classification ACOG Criteria
Primary Purpose Defines severe HELLP syndrome Identifies mild and severe HELLP
Hemolysis (MAHA) Required (schistocytes, low haptoglobin, elevated bilirubin >1.2 mg/dL) Required (Peripheral smear evidence or bilirubin >1.2 mg/dL or low haptoglobin)
LDH (Lactate Dehydrogenase) >600 IU/L >600 IU/L
AST/ALT (Liver Enzymes) AST/ALT >70 IU/L AST/ALT ≥2× upper limit of normal (≈70 IU/L)
Platelet Count ≤100 × 10⁹/L ≤100 × 10⁹/L (Class I)
100–150 × 10⁹/L (Class II & III)
Classification Tiers only detects severe HELLP Class I: Platelets ≤50 × 10⁹/L
Class II: Platelets 50–100 × 10⁹/L
Class III: Platelets 100–150 × 10⁹/L