Investigations & Diagnosis

Initial tests:

• • Morning cortisol (9 am)
  • U&Es (Low Sodium, High Potassium)
  • LFTs
  • FBC
  • Calcium
  • TFTs

Cortisol results interpretation:

• <100 nmol/L: admit
• 100-500 nmol/L: endocrine referral
• >500: Normal

Secondary care:

• Short synacthen test
  • Cortisol remains low in primary adrenal insufficiency
  • Cortisol increases in secondary adrenal insufficiency
• Other tests: Renin:aldosterone test, Serum DHEA, Autoantibodies