RAAS Status

LABOKLIN Service ID: 497


Renin-angiotensin-aldosterone system status

Diagnosis

Differentiated analysis of disorders of blood pressure and electrolyte regulation:

  • differentiation between primary and secondary hyperaldosteronism
  • cardiac and renal diseases
  • systemic hypertension
  • monitoring of pharmacological RAAS blockades (ACE inhibitors, ARBs (angiotensin receptor blockers), MRAs (mineralocorticoid receptor antagonists))

    • Material

    Serum 1ml (centrifuged and separated shortly after coagulation, pipetted off; frozen until arrival at the laboratory – please contact the laboratory for transport options in advance)

    Parameter

    Renin activity, angiotensin I+II concentration and aldosterone concentration (quantitative)

    Method

    Liquid chromatography-mass spectrometry (LCMS)

    Species list

    Dog, cat

    Duration

    3–6 working days

    Assessment

    Angiotensin I (Ang I)
    ↑ Ang I = increased renin release (volume deficiency, Na deficiency, heart failure, medication)
    ↓ Ang I = decreased renin release (hypervolaemia, primary hyperaldosteronism)

    Angiotensin II (Ang II)
    ↑ Ang II = increased ACE activity or RAAS activation
    ↓ Ang II = successful ACE blockade, e.g. after administration of enalapril, or low activation of the renin-angiotensin-aldosterone system (e.g. in primary hyperaldosteronism)

    Aldosterone
    ↑ Aldosterone while ↓ Ang II → Aldosterone escape = autonomous, ACE-independent aldosterone production
    ↑ Aldosterone while ↑ Ang II → classic RAAS activation
    ↓ Aldosterone → suppressed RAAS axis or hypokalaemia

    Renin activity (PRA-S) – indirectly determined via Ang I + Ang II
    ↑ PRA-S = renin release through negative feedback (e.g. after administration of ACE inhibitors, volume deficiency)
    ↓ PRA-S = renin suppression (volume overload, hypertension, high sodium intake, primary hyperaldosteronism)

    ACE activity (ACE-S) – determined by the Ang II/Ang I ratio
    ↑ ACE-S = high conversion of Ang I → Ang II → active RAAS
    ↓ ACE-S = functional inhibition of ACE, e.g. after administration of enalapril, or low Ang II production

    AA2 ratio (aldosterone/Ang II) – the most important marker for functional examination
    low AA2: aldosterone proportional to Ang II → classic axis intact
    high AA2: aldosterone disproportionately high despite low Ang II → Ang II-independent aldosterone production (primary hyperaldosteronism)

    Remark

    Note: The sample must arrive frozen at the laboratory. Please contact laboratory for transport options.