HELLP Syndrome


Indications for Testing

  • Pregnant patient presenting with clinical picture of preeclampsia, thrombocytopenia, or acute liver failure

Criteria for Diagnosis

  • Patients lacking all 3 of the criteria for HELLP (hemolysis, elevated liver enzymes, and low platelets) can be deemed partial HELLP

Laboratory Testing

  • CBC – anemia, thrombocytopenia (<100,000/mm3 to meet criteria)
    • Peripheral smear – helmet cells, burr cells, schistocytes (all signs of microangiopathic hemolysis)
  • Liver function tests – elevated
    • Aspartate aminotransferase (AST) – 2 times the upper reference limit (to meet criteria)
    • Lactate dehydrogenase (LD) – markedly elevated (≥600 U/L to meet criteria)
      • LD criteria should be based on the upper limits of normal values in the lab where specimen is processed

Differential Diagnosis

Clinical Background

HELLP syndrome refers to the constellation of Hemolysis, Elevated Liver function tests, and Low Platelet count seen in pregnant women and sometimes considered to be a severe form of eclampsia.


  • Incidence – 4-5/1,000 pregnancies
    • 5-10% of pregnancies with preeclampsia
    • 30-50% of pregnancies with eclampsia
  • Age – childbearing years
  • Sex – exclusively in pregnant or postpartum females

Risk Factors

  • Caucasian race
  • Multiparity
  • Age – >34 years
  • Presence of preeclampsia or eclampsia
  • Fetus affected with fatty acid oxidation defect – ie, defects such as long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency


  • Placenta in preeclampsia is poorly perfused, which releases factors that create endothelial dysfunction
  • Endothelial dysfunction causes platelet aggregation and altered ratio of thromboxane to prostacyclin
  • Thrombin-induced activation of the coagulation cascades leads to hemolytic anemia and multiorgan microvascular injury

Clinical Presentation

  • Usually occurs during pregnancy
    • 2/3 of patients are diagnosed antepartum
    • Typically does not present prior to 3rd trimester
    • Postpartum presentation usually within first week
  • Symptoms
    • Nonspecific – malaise, fatigue
    • Gastrointestinal – right upper quadrant pain, nausea, emesis
    • Central nervous system – headache, confusion
    • Cardiovascular – hypertension
  • Complications
    • Maternal
    • Fetal/perinatal
      • Prematurity
      • Placental insufficiency
      • Intrauterine growth restriction
      • Neonatal intraventricular hemorrhage


  • Consider fetus delivery  
    • Medical emergency with maternal mortality of 1-2% and fetal mortality of 10-30%
    • ≥34 weeks – immediate delivery if maternal status not rapidly improving
    • <34 weeks but ≥27 weeks – delivery within 48 hours after medical stabilization
    • <27 weeks – conservative management based on maternal health
      • Conservative treatment is contraindicated in women with DIC
  • Glucocorticosteroid therapy
    • Nonrandomized studies suggest therapy may improve outcomes
      • Maternal dosing – high dose versus repeated dose
      • Fetal dosing – based on standard treatment to promote fetal lung maturity

Indications for Laboratory Testing

  • Tests generally appear in the order most useful for common clinical situations
  • Click on number for test-specific information in the ARUP Laboratory Test Directory
Test Name and Number Recommended Use Limitations Follow Up
CBC with Platelet Count and Automated Differential 0040003
Method: Automated Cell Count/Differential

Use with hepatic function panel and LD in the diagnosis of HELLP

Hepatic Function Panel 0020416
Method: Quantitative Enzymatic/Quantitative Spectrophotometry

Use with LD and CBC in the diagnosis of HELLP

Panel includes albumin; alkaline phosphatase; aspartate aminotransferase; alanine aminotransferase; bilirubin, direct; protein; bilirubin, total

Lactate Dehydrogenase, Serum or Plasma 0020006
Method: Quantitative Enzymatic

Use with hepatic function panel and CBC in diagnosis of HELLP