HELLP Syndrome Diagnostic Criteria
HELLP syndrome is diagnosed by the presence of three components: hemolysis (evidenced by schistocytes on peripheral smear, elevated LDH, or low haptoglobin), elevated liver enzymes (AST/ALT), and thrombocytopenia with platelet count below 100,000/mm³. 1, 2
Core Diagnostic Components
Hemolysis
- Microangiopathic hemolytic anemia must be confirmed by peripheral blood smear showing schistocytes (fragmented red blood cells) resulting from endothelial damage with fibrin deposition 3
- Elevated LDH serves as a dual marker reflecting both hemolysis extent and hepatic dysfunction 1, 3
- Additional supportive findings include elevated indirect bilirubin or low serum haptoglobin levels 2
Elevated Liver Enzymes
- AST, ALT, LDH, and total bilirubin are the most useful markers for following disease progression and correlate with adverse maternal outcomes 1
- Significant elevation in liver enzymes must be present, though specific thresholds vary by classification system 2
Low Platelet Count
- Platelet count below 100,000/mm³ is the threshold established by ACOG for diagnosis and indicates severe thrombocytopenia with significant maternal risk 1, 2
- The degree of thrombocytopenia directly correlates with severity of liver dysfunction and predicts adverse maternal outcomes 4, 1, 3
- Platelet count serves as one of the two most important clinical tools for disease assessment alongside LDH 3, 5
Clinical Context and Timing
- HELLP syndrome typically develops in the third trimester in patients with severe preeclampsia, though approximately 30% of cases occur or worsen postpartum (within 48-72 hours after delivery) 1, 6, 7
- The syndrome can occur in the absence of classic preeclampsia or eclampsia features, making diagnosis challenging 5, 6
- Laboratory abnormalities peak 24 hours after delivery and may take up to 10 days to fully resolve 3
Associated Severe Features Requiring Urgent Intervention
When HELLP syndrome is present, look for these additional severe manifestations that mandate immediate delivery 4:
- Blood pressure exceeding 160/90 mmHg
- Proteinuria >5 g/24 hours
- Oliguria <400 mL/24 hours
- Cerebral signs or symptoms
- Pulmonary edema
- Right upper quadrant or epigastric pain (present in 65% of symptomatic patients) - this should immediately trigger imaging to rule out subcapsular hematoma or hepatic rupture 1
Critical Diagnostic Pitfalls
- Do not wait for all three components to be severely abnormal - partial HELLP syndrome exists and still carries significant risk 2, 7
- Do not confuse with other conditions including acute fatty liver of pregnancy, idiopathic thrombocytopenia, hemolytic uremic syndrome, or appendicitis 6
- Obtain abdominal imaging (ultrasound or CT) when hepatic involvement is suspected to rule out hepatic hemorrhage, infarct, or rupture 1
Essential Preoperative Laboratory Workup
Before any surgical intervention, obtain 4:
- Platelet count, white blood cell count, PCV
- Partial thromboplastin time, fibrinogen, fibrin degradation products
- Peripheral blood smear
- Liver function tests (AST, ALT, LDH, bilirubin)
- Serum creatinine, urea, and uric acid
- Chest X-ray to exclude pulmonary edema
- ECG examination