What labs should I order for someone with a nondisplaced sternal fracture that occurred 5 days ago?

Laboratory Testing for Nondisplaced Sternal Fracture at 5 Days Post-Injury

At 5 days post-injury with a nondisplaced sternal fracture, no routine laboratory testing is indicated if the patient was appropriately evaluated at initial presentation with normal ECG and cardiac troponins. 1

Initial Assessment Context (What Should Have Been Done)

The critical window for cardiac injury screening has already passed. At initial presentation, the following labs should have been obtained:

• ECG and cardiac troponin levels - These are the only mandatory tests for sternal fractures, as patients with normal results can be safely discharged with low probability for cardiac blunt trauma 1, 2
• Complete blood count (CBC) - To assess for anemia from occult bleeding, though this is primarily relevant in the acute setting 3
• Basic metabolic panel - To evaluate electrolytes if there were concerns about prolonged immobilization or dehydration 3

Current Laboratory Needs at 5 Days Post-Injury

If Initial Workup Was Normal

No additional labs are needed unless new symptoms develop 1. The patient should focus on:

• Pain management optimization
• Early mobilization and physical therapy 1
• Monitoring for complications like deep vein thrombosis if mobility has been limited 1

If Initial Workup Was Never Performed (Red Flag Scenario)

This represents a significant gap in care. You should now obtain:

• 12-lead ECG - To identify any delayed arrhythmias or ischemic changes, though the highest risk period has passed 2, 4
• Cardiac troponin - While less sensitive at 5 days, persistent elevation would indicate ongoing myocardial injury requiring further evaluation 2, 4
• CBC - To assess for delayed anemia from slow bleeding or nutritional deficiency affecting healing 3

If New Symptoms Have Developed

Chest pain, dyspnea, or palpitations warrant immediate evaluation with:

• Repeat ECG and serial cardiac troponins - To exclude delayed cardiac complications 2, 4
• Arterial blood gas - If respiratory compromise is present 3
• D-dimer - If pulmonary embolism is suspected from immobility 1

Special Considerations for Elderly Patients

If the patient is elderly (>65 years), additional labs should be considered regardless of symptom status:

• Vitamin D and calcium levels - To assess for underlying osteoporosis that may have contributed to the fracture 1
• Thyroid function tests - If there are concerns about metabolic bone disease 1
• Comprehensive metabolic panel - To evaluate renal function before initiating calcium/vitamin D supplementation 1

Common Pitfalls to Avoid

• Do not order routine "trauma panels" at 5 days post-injury for an isolated, nondisplaced sternal fracture - this represents unnecessary testing and cost 1
• Do not assume normal vital signs exclude cardiac injury - ECG and troponins are far more sensitive than clinical examination alone 3, 2
• Do not order echocardiography if ECG and troponins were normal at presentation, as this adds no diagnostic value for isolated sternal fractures 1, 2
• Do not delay mobilization waiting for lab results if the patient is otherwise stable - early movement is crucial for recovery 1

Disposition and Follow-Up

The focus at 5 days should shift from acute injury detection to rehabilitation and complication prevention, not laboratory monitoring 1. Ensure the patient has:

• Adequate analgesia for continued mobilization 1
• Physical therapy referral for range-of-motion exercises 1
• Instructions to restrict above-chest-level activities until fracture healing 1
• Clear return precautions for new cardiac or respiratory symptoms 2