What are the laboratory tests for preeclampsia?

From the Guidelines

Preeclampsia labs should include a complete blood count (CBC), comprehensive metabolic panel (CMP), urine protein measurement (either spot protein/creatinine ratio or 24-hour collection), uric acid level, and coagulation studies to diagnose and monitor this pregnancy complication. The essential labs help assess for hemolysis, thrombocytopenia, liver function, kidney function, and proteinuria, which are key diagnostic criteria for preeclampsia.

• A CBC helps assess for hemolysis and thrombocytopenia, while the CMP evaluates liver function (AST, ALT) and kidney function (creatinine, BUN) 1.
• Proteinuria is a key diagnostic criterion, with significant proteinuria defined as ≥300 mg in a 24-hour urine collection or a protein/creatinine ratio ≥0.3 1.
• Additional specialized tests may include lactate dehydrogenase (LDH) to check for hemolysis, and in severe cases, tests for disseminated intravascular coagulation (DIC) 1. These labs are crucial because preeclampsia involves multi-organ dysfunction, particularly affecting the kidneys, liver, and blood clotting systems. Regular monitoring of these parameters helps healthcare providers assess disease progression and determine appropriate management, including timing of delivery, which is the definitive treatment for preeclampsia.
• The frequency of lab tests should be at least twice weekly, and more frequently if there is a change in clinical status or if the patient has severe preeclampsia 1.
• The labs should be used to monitor for signs of worsening disease, such as decreasing platelet count, increasing liver enzymes, and decreasing kidney function, which can indicate the need for delivery 1.

From the Research

Preeclampsia Labs

Preeclampsia is a pregnancy-specific multisystem disorder characterized by new-onset hypertension and proteinuria after 20 weeks of gestation 2. The diagnosis and management of preeclampsia involve various laboratory tests to assess end-organ damage. Some of the key laboratory tests used to evaluate preeclampsia include:

• Serum uric acid levels: Elevated serum uric acid levels are associated with kidney dysfunction and are considered a predictor of the severity of preeclampsia 3.
• Liver function tests: Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels are often elevated in patients with preeclampsia, indicating liver damage 3, 4.
• Renal function tests: Blood urea nitrogen and creatinine levels are used to assess kidney function in patients with preeclampsia 5.
• Platelet count: Thrombocytopenia is a common feature of preeclampsia, and platelet count is often used to monitor disease severity 6.
• Proteinuria: The presence of protein in the urine is a key diagnostic criterion for preeclampsia 2.

Laboratory Test Results

The results of these laboratory tests can vary depending on the severity of preeclampsia and the presence of end-organ damage. For example:

• Elevated serum uric acid levels are associated with increased risk of kidney dysfunction and poor outcomes 3.
• Abnormal liver function tests are associated with increased risk of liver damage and poor outcomes 3, 4.
• Thrombocytopenia is associated with increased risk of bleeding complications and poor outcomes 6.
• Proteinuria is a key diagnostic criterion for preeclampsia, and the severity of proteinuria is associated with disease severity 2.

Screening Recommendations

Based on the available evidence, the following screening recommendations can be made:

• Serum uric acid and liver function tests may be useful in evaluating patients with preeclampsia, particularly those with severe disease 3, 4.
• Renal function tests, such as blood urea nitrogen and creatinine, may be useful in monitoring kidney function in patients with preeclampsia 5.
• Platelet count and proteinuria should be monitored regularly in patients with preeclampsia to assess disease severity and guide management 2, 6.