What labs should be checked in a patient with acute arterial and venous thrombosis in septic shock?

Laboratory Tests for Patients with Acute Arterial and Venous Thrombosis in Septic Shock

In patients with both acute arterial and venous thrombosis in septic shock, a comprehensive coagulation panel including thromboelastography (TEG) should be obtained, along with routine sepsis workup, to guide management and improve outcomes. 1

Essential Laboratory Tests

Routine Sepsis Workup

• Complete blood count with platelet count - critical for assessing thrombocytopenia, which may require transfusion at different thresholds based on bleeding risk 2
• Blood cultures (at least two sets, aerobic and anaerobic) before starting antimicrobial therapy 3
• Serum lactate level - important marker of tissue hypoperfusion and predictor of mortality 3
• Basic metabolic panel - to assess organ function and guide fluid resuscitation 3
• Arterial blood gas - to evaluate acid-base status and oxygenation 3

Coagulation Studies

• Prothrombin time (PT)/International Normalized Ratio (INR) - prolongation indicates coagulopathy and predicts mortality 4
• Activated partial thromboplastin time (aPTT) - persistent prolongation on day 3 is a strong predictor of mortality 4
• Fibrinogen level - decreased in consumption coagulopathy 3
• D-dimer - elevated in both sepsis and thrombosis 5
• Fibrin degradation products - marker of fibrinolysis 5

Advanced Coagulation Assessment

• Thromboelastography (TEG) - provides real-time assessment of clot formation, strength, and dissolution; can detect hypocoagulability even when conventional tests are normal 6
• Thrombin generation assay - persistent deficit on day 3 is an independent predictor of mortality 4
• Platelet function tests - septic patients often have decreased platelet aggregation and secretion responses 7

Disseminated Intravascular Coagulation (DIC) Evaluation

• Calculate International Society on Thrombosis and Haemostasis (ISTH) DIC score using:
  • Platelet count
  • Fibrin-related markers (D-dimer or fibrin monomers)
  • Prolonged PT
  • Fibrinogen level 5

Monitoring and Management Thresholds

Platelet Transfusion Guidelines

• Transfuse platelets when counts are <10,000/mm³ in the absence of bleeding 2
• Transfuse platelets when counts are <20,000/mm³ if significant bleeding risk exists 2
• Maintain platelet counts ≥50,000/mm³ for active bleeding, surgery, or invasive procedures 2

Blood Product Administration

• Transfuse red blood cells when hemoglobin <7.0 g/dL (target 7.0-9.0 g/dL) once tissue hypoperfusion has resolved 3
• Do not use fresh frozen plasma to correct laboratory clotting abnormalities in the absence of bleeding or planned invasive procedures 3
• Do not use antithrombin for treatment of sepsis and septic shock 3

Monitoring Frequency

• Monitor coagulation parameters at admission and after 6 hours of adequate fluid resuscitation 1
• Repeat coagulation studies daily, with special attention to day 3 parameters which have strong prognostic value 4
• Monitor blood glucose every 1-2 hours until stable, then every 4 hours 3

Important Considerations

• Hypocoagulability on TEG (especially K >3, α <53°, and MA <50 mm) is associated with increased mortality even when PT and aPTT are normal 6
• Persistent coagulopathy after initial resuscitation is a stronger predictor of mortality than initial coagulopathy 4
• Early detection of DIC using the ISTH scoring system helps identify patients at higher risk of organ dysfunction and death 5
• Platelet-leukocyte interactions are significantly increased in early sepsis and may contribute to microvascular thrombosis 7