Addison’s Disease: Test and Diagnosis

1st order laboratory parameters – obligatory laboratory tests.

  • Hormone diagnostics
    • Stage I
      • Cortisol, free (8:00 a.m.) [↓]; cortisol in 24-hour urine [↓] Note: A normal baseline cortisol level (approximately 30% of cases) does not rule out Addison’s disease!
      • ACTH [↑]
      • TSH
      • Aldosterone [↓; serum aldosterone was below the detection limit in two-thirds of patients] ]
      • Renin [↑]
    • Stage II
      • ACTH short test (stimulation of the adrenal glands with exogenous ACTH (Synacten test) leads to a significant cortisol release if functional reserves are present) – performed if the single cortisol value is decreased [in Addison’s disease, cortisol cannot be stimulated or can only be stimulated insufficiently; 99% of the examined patients no increase in cortisol secretion can be triggered (< 500 nmol/l)].
      • CRH test
      • TRH test
      • FT3
      • FT4
      • TPO-Ak: antibodies against thyroid peroxidase (TPO).
      • Antibodies against TSH receptor (TRAK).
      • Antibodies to adrenal cortex [AKNNR]
      • 21-Hydroxylase autoantibodies (21-hydroxylase (CYP21) is a key enzyme in steroid biosynthesis and is the main antigen of AK against adrenal cortex) [Test for 21-hydroxylase autoantibodies was 100% positive].
  • Small blood count
  • Differential blood count [eosinophilia]
  • Fasting glucose (fasting blood glucose) [hypoglycemia (hypoglycemia)], oral glucose tolerance test (oGTT) if necessary.
  • Electrolytes – sodium, potassium [hyponatremia / sodium deficiency, hyperkalemia / potassium excess].

Laboratory parameters 2nd order – depending on the results of the history, physical examination and mandatory laboratory parameters – for differential diagnostic clarification.

  • Inflammatory parameters – CRP (C-reactive protein).
  • Autoantibodies against 21-hydroxylase (21-OH antibodies) – in V. a. autoimmune genesis.
  • Exclusion of infections:
    • Tbc-PCR (molecular genetic method) – in case of V. a. tuberculosis of the adrenal cortex (NNR).
    • HIV diagnostics
    • Mycoses (histoplasmosis, coccidioidomycosis, cryptococcosis).
  • Liver parameters – alanine aminotransferase (ALT, GPT), aspartate aminotransferase (AST, GOT), glutamate dehydrogenase (GLDH) and gamma-glutamyl transferase (gamma-GT, GGT).
  • Renal parameters – urea, creatinine, cystatin C or creatinine clearance, as appropriate.