What tests should be done before prescribing steroids (corticosteroids)?

Pre-Steroid Testing Requirements

Before prescribing corticosteroids, patients should undergo tuberculin skin testing, blood pressure measurement, glycemic control assessment, serum potassium testing, and bone mineral density evaluation to minimize serious adverse effects. 1, 2

Essential Pre-Steroid Laboratory Tests

Infectious Disease Screening

• Tuberculosis screening: Perform tuberculin skin testing before initiating steroid therapy, as steroids may suppress the immune response to skin tests 1
• Consider prophylaxis with trimethoprim/sulfamethoxazole for Pneumocystis carinii in high-risk patients receiving >15 mg prednisone daily for >3 weeks 1
• Consider isoniazid prophylaxis for patients with positive tuberculin skin tests or those at high risk 1

Metabolic Parameters

• Blood glucose: Screen for undiagnosed or poorly controlled diabetes mellitus 3
• Serum potassium: Monitor for electrolyte abnormalities 1
• Blood pressure: Measure and document baseline values 1

Bone Health Assessment

• Calcium and vitamin D levels: All patients starting corticosteroids should receive 800-1000 mg calcium and 800 IU vitamin D daily 1
• Bone mineral densitometry: Arrange as soon as possible, especially for high-risk patients (previous fracture, prolonged steroid use, age >40 years) 1
• FRAX risk assessment: Calculate 10-year fracture risk (www.shef.ac.uk/FRAX) 1

Adrenal Function

• Morning cortisol and ACTH levels: For patients with suspected adrenal insufficiency or those previously on steroids 2
• Note: Laboratory confirmation of adrenal insufficiency should not be attempted in patients on high-dose corticosteroids until treatment is ready to be discontinued 2

Special Considerations

Medication Discontinuation Before Testing

When testing adrenal function, certain medications require specific washout periods 1, 2:

• Oral antihistamines: 3-10 days
• Cetirizine: 5-7 days
• Diphenhydramine: 3 days
• Hydroxyzine: 7-10 days
• Oral/intramuscular/intravenous steroids: 3 days-2 weeks

High-Risk Patient Identification

Screen for patients at increased risk of steroid complications 1, 3:

• Previous fragility fracture
• Prolonged (>3 months) or repeated courses of steroids
• Age >40 years
• Diabetes or risk factors for diabetes
• Hypertension
• History of peptic ulcer disease
• Family history of osteoporosis

Monitoring During Steroid Therapy

• Blood pressure: Regular monitoring throughout treatment
• Blood glucose: Regular monitoring, especially in those with risk factors for diabetes
• Bone mineral density: Repeat at 1 year for patients on long-term steroids, then every 2-3 years if stable, or annually if declining 1
• Morning cortisol and ACTH: Consider monthly monitoring for 6 months, then every 3 months for 6 months, then every 6 months for 1 year in patients at risk for adrenal suppression 1

Common Pitfalls to Avoid

1. Failing to screen for tuberculosis before starting steroids, which can lead to reactivation of latent TB 1
2. Not providing calcium and vitamin D supplementation, increasing osteoporosis risk 1
3. Overlooking diabetes risk in patients without known history of diabetes 3
4. Testing adrenal function while patient is still taking steroids, which will yield inaccurate results 2
5. Abruptly stopping steroids in patients on long-term therapy, which can precipitate adrenal crisis 2

Following these testing protocols before prescribing corticosteroids will help minimize the significant risks associated with steroid therapy, including osteoporosis, adrenal suppression, hyperglycemia, hypertension, and immunosuppression.