Recommended Blood Tests for Patients with Prolonged Immobility ("Long Lie")
A comprehensive laboratory panel for patients with prolonged immobility should include complete blood count (CBC), comprehensive metabolic panel, coagulation studies, cardiac biomarkers, and urinalysis to assess for complications. 1
Core Laboratory Tests
Initial Assessment
Complete Blood Count (CBC)
- Hemoglobin/hematocrit: Assess for anemia
- White blood cell count with differential: Evaluate for infection/inflammation
- Platelet count: Monitor for thrombocytopenia 1
Comprehensive Metabolic Panel
- Creatinine and BUN: Assess renal function and dehydration
- Electrolytes (sodium, potassium, calcium, phosphate): Monitor for imbalances
- Liver function tests: Evaluate hepatic function 1
Creatine Kinase (CK)
- Critical for detecting rhabdomyolysis (>5 times upper limit of normal indicates significant muscle damage)
- Should be monitored serially every 6-12 hours initially until stabilization 1
Coagulation and Thrombotic Risk Assessment
- Coagulation Studies
- Prothrombin Time (PT)/International Normalized Ratio (INR)
- Activated Partial Thromboplastin Time (aPTT)
- D-dimer: Elevated levels suggest possible deep vein thrombosis or pulmonary embolism
- Fibrinogen: Assess for consumption coagulopathy 1
Additional Important Tests
Cardiac Biomarkers
- Troponin: Assess for cardiac injury
- BNP/NT-proBNP: Consider when cardiac pathology is suspected 1
Urinalysis
- Evaluate for myoglobinuria (indicative of rhabdomyolysis)
- Assess hydration status and renal function 1
Monitoring and Follow-up Testing
- Serial Testing Schedule
- CK, renal function, and electrolytes: Every 6-12 hours initially
- Continue monitoring until values stabilize or normalize
- Coagulation studies: Repeat if initially abnormal or if clinical condition changes 1
Special Considerations for High-Risk Populations
Elderly Patients
- Lower threshold for cardiac biomarker testing
- More vigilant monitoring of renal function
- Consider more frequent electrolyte monitoring 1
Patients on Anticoagulants
- More extensive coagulation testing
- Consider specific factor assays if abnormalities are detected 1
Common Pitfalls to Avoid
Delayed Laboratory Evaluation
- Failing to obtain initial labs promptly may miss early signs of rhabdomyolysis or electrolyte abnormalities
- Single measurements may not detect evolving complications; serial testing is essential 1
Inadequate Monitoring
- Laboratory values should guide aggressive fluid resuscitation when indicated by elevated CK or evidence of renal injury
- Patients with prolonged immobility are at high risk for thrombotic events, requiring vigilant monitoring of coagulation parameters 1
Overlooking Medication Effects
- For patients on medications like fondaparinux, regular monitoring of complete blood counts (including platelet counts), serum creatinine, and stool occult blood tests is recommended 2
By systematically evaluating these laboratory parameters, clinicians can effectively identify and manage the potential complications associated with prolonged immobility, including rhabdomyolysis, acute kidney injury, electrolyte imbalances, and thrombotic events.