What is the recommended approach when coagulation (coags) studies, including type and screen, are ordered?

Coagulation Studies in Clinical Practice: When to Order Type and Screen

Routine coagulation studies and type and screen should not be ordered for all patients but should be based on specific clinical indications, patient history, anticipated hemorrhagic complications, and institutional policies.

Indications for Type and Screen

• A routine blood cross-match is not necessary for healthy and uncomplicated patients undergoing vaginal or operative delivery 1
• The decision to order a blood type and screen should be based on:
  • Patient's medical history (e.g., bleeding disorders, previous transfusions) 1
  • Anticipated hemorrhagic complications (e.g., placenta accreta in patients with placenta previa and previous uterine surgery) 1
  • Local institutional policies 1

Indications for Coagulation Studies

Recommended clinical scenarios:

• Patients with history of bleeding disorders 1
• Patients on anticoagulant therapy 1
• Patients with liver disease 1
• Patients with suspected coagulopathy (e.g., DIC) 1
• Patients with preeclampsia or HELLP syndrome 1
• Prior to certain high-risk procedures 1
• Patients with acute trauma requiring blood product administration 1

Not routinely recommended for:

• Healthy patients without bleeding history 1, 2
• Low-risk procedures including:
  • Diagnostic and therapeutic paracentesis 1
  • Common forms of thoracentesis 1
  • Upper endoscopy for screening/banding of esophageal varices 1
  • Diagnostic colonoscopy 1

Components of Coagulation Studies

Standard coagulation studies typically include:

• Prothrombin time (PT)/International Normalized Ratio (INR) 3, 4
• Activated partial thromboplastin time (aPTT) 3, 4
• Platelet count 1
• Fibrinogen level (when indicated) 1, 4

Clinical Considerations

Pre-analytical factors affecting results:

• Hemolyzed, icteric, or lipemic samples 5
• Improper blood-to-anticoagulant ratio 5
• Contamination with other anticoagulants 5
• Clotted specimens 5

Limitations of coagulation testing:

• Low sensitivity (1.0%-2.1%) for detection of clinically significant bleeding disorders 3
• Isolated prolongation of PT is rarely clinically significant 6
• One-third of isolated prolonged aPTT cases are clinically insignificant 6
• Many abnormal results do not correlate with bleeding risk 2, 6

Best Practices

• Avoid unnecessary coagulation testing, which has been shown to be rampant in clinical practice 2, 3
• Current guidelines recommend against routine use of screening PT and aPTT in preoperative patients undergoing non-cardiac/vascular surgery 3
• When coagulation studies are indicated, platelet count and fibrinogen level are the standard of care assessment for patients when determination of values is indicated before a procedure 1
• For patients on anticoagulation therapy, testing should ideally be performed 1-2 weeks after discontinuation of treatment or when INR is less than 1.5 1

Common Pitfalls to Avoid

• Ordering coagulation panels when individual tests would suffice 2
• Failing to recognize that abnormal coagulation screens may not always correlate with clinically significant decreases in coagulation factors 6
• Ordering type and screen for all patients regardless of bleeding risk 1
• Interpreting results without considering pre-analytical variables 5
• Testing for lupus anticoagulant while patient is on anticoagulation therapy 1