What laboratory tests should be ordered as a comprehensive HELLP syndrome panel for a pregnant patient with suspected hemolysis, elevated liver enzymes, and low platelets under Alberta Health Services?

HELLP Syndrome Laboratory Panel

For suspected HELLP syndrome in Alberta Health Services, order a comprehensive panel including: complete blood count with peripheral blood smear, platelet count, LDH, AST, ALT, total and indirect bilirubin, haptoglobin, fibrinogen, PT/aPTT, fibrin degradation products (D-dimer), creatinine, urea, uric acid, and urinalysis for proteinuria. 1

Core Diagnostic Tests

The diagnosis of HELLP syndrome requires laboratory confirmation of all three components, with specific tests targeting each element:

Hemolysis Assessment

• Peripheral blood smear (essential for identifying schistocytes and microangiopathic hemolytic anemia) 1
• LDH - most reliable marker for hemolysis and disease monitoring 2
• Indirect bilirubin (elevated, though rarely marked in HELLP) 1
• Haptoglobin (decreased, supportive test) 2, 3

Liver Enzyme Evaluation

• AST (aspartate aminotransferase) - typically >200 U/L in severe cases 1
• ALT (alanine aminotransferase) - typically >159 U/L in severe cases 1
• Total bilirubin - usually ≤18 μmol/L; if markedly elevated, investigate alternative causes 1
• LDH isoenzymes (supportive) 2

Platelet and Coagulation Assessment

• Platelet count - diagnostic threshold <100,000/mm³; critical threshold ≤40,000/mm³ predicts hemorrhagic complications 3, 4
• PT (prothrombin time) and aPTT (activated partial thromboplastin time) - usually normal in HELLP, helps exclude DIC 1
• Fibrinogen - typically normal; low levels suggest DIC 1
• Fibrin degradation products (D-dimer) - elevated (>10 μg/L indicates microangiopathy) 1

Additional Essential Tests

Renal Function

• Creatinine, urea, and uric acid - assess for renal involvement and severity 1
• Urinalysis - document proteinuria (>5 g/24h indicates severe preeclampsia) 1

Supportive Laboratory Work

• Complete blood count with hemoglobin and PCV 1
• White blood cell count 1
• Total protein and albumin (decreased in severe cases) 1
• Phosphate (may be decreased) 1

Monitoring Strategy

LDH and platelet count are the two most critical tests for monitoring disease progression 2. The evidence shows maternal mortality ranges from 2-24% with rapid disease progression 1, making serial monitoring essential.

Common Pitfalls to Avoid

1. Do not rely on alkaline phosphatase - typically normal in HELLP and not diagnostically useful 1

2. Distinguish from other conditions: The panel helps exclude acute fatty liver of pregnancy (AFLP), thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, and acute viral hepatitis 5, 3

3. Recognize atypical presentations: Some patients present without hypertension or proteinuria initially, making laboratory confirmation critical 3

4. Monitor for sepsis: If fever or rapid deterioration occurs, add blood cultures, procalcitonin, and inflammatory markers (IL-6) as sepsis can complicate or mimic HELLP 6

5. Check glucose levels: Severe hypoglycemia has been reported with HELLP syndrome 1

Clinical Context

The platelet count has prognostic significance: intrapartum counts ≤40,000/μL predict significant postpartum hemorrhagic complications, while counts >40,000/μL are associated with lower bleeding risk 4. This threshold should guide transfusion decisions and surgical planning.

The degree of thrombocytopenia correlates directly with liver dysfunction severity 1, making both parameters essential for risk stratification and management decisions.