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A B C D E F G H I J K L M N O P Q

Test Identifier Information

 
Registration CodeREND
Method

Chemiluminescence

Diagnostic Use / Indications

Aetiology of hypertension (primary hyperaldosteronism, and other mineralocorticoid excess states associated with high blood pressure, renal artery stenosis, renin secreting tumours). Best done in conjunction with measurement of plasma aldosterone.

Localising renal ischaemic disease (renal vein renin sampling).

Diagnosis of primary adrenocortical insufficiency and assessing adequacy of mineralocorticoid replacement.

Diagnosis of Bartter's syndrome.

Diagnosis of hypovolaemic disorders (eg patients presenting with hyponatraemia, postural hypotension etc).

Diagnosis of hyporeninaemic syndromes.

External Price$39.31(Exclusive of GST)
  

Specimen Collection

 
Pre-Testing Requirements

Patient's posture, salt intake, drug therapy, age and time of sampling affect levels. Potassium depletion and/or hypokalaemia lower renin - aldosterone secretion.
Outpatients are best screened as follows:
If possible stop non-essential anti-hypertensives for 2 weeks before sampling.  Many hypotensive drugs alter renin - aldosterone levels; preferred agents are Alpha-blockers (Doxazosin, Prazosin) and non-dihydropyridine calcium channel blockers (Verapamil, Diltiazem) since they do not greatly alter renin - aldosterone. Screening tests for primary hyperaldosteronism and related conditions can still be done in patients on betablockers, ACE inhibitors and/or diuretics, BUT interpretation must allow for the potent effects these drugs have on the renin - aldosterone axis. Patients should attend (non-fasting) prior to 10.00 am for "ambulant sampling of plasma aldosterone and renin. It is usually wise to check plasma Na, K and creatinine at the time of sampling.

Inpatients are screened as above and should be ambulated for at least 30 minutes before sampling.

Other protocols involving plasma aldosterone/renin measurement include saline suppression (2L saline over 4 hours), 4-hour posture test (08.00 overnight supine aldosterone, repeated after 4 hr of upright posture) and tests using ACTH stimulation or dexamethasone suppresion.

 

 

 

If patient is on high dose Biotin therapy (>5 mg/day), wait until at least 8 hours after last dose to take blood sample.

Specimen Collection Protocols

EDTA blood collected and centrifuged at room tempearature. Plasma stored and transported deep-frozen. Thawed samples will not be assayed. If Renin or Aldostrone-Renin ratio is required, preferably collect blood before 10 am.

For Renin alone collect 1.5 ml (paediatric 1.2 ml).

 

Patient SpecimenBlood 2.5ml EDTA(Lav) for Aldosterone-Renin ratio
Paediatric SpecimenBlood 1.5 ml EDTA(Lav) for Aldosterone-Renin ratio
Sample Delivery to LabImmediately to enable separating and freezing
  

Instructions for Referral to CHLabs

 
Aliquot InstructionsMinimum 0.6 ml EDTA plasma for Renin alone or 1.0 ml for Aldosterone - Renin ratio. Snap frozen.
Aliquot Transport to CHLFrozen
  

CHLabs Laboratory

 
DepartmentEndocrinology Laboratory
Contact Details Email Email
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Contact Phone Number(03) 3640886 | x80886
Test AvailabilityBatched twice weekly
Turnaround Time7 days
Reference Interval

07.00 - 10.00 Ambulant (adult): 5.3 - 99.1 mIU/L

07.00 - 10.00 Supine (adult): 4.2 - 59.7 mIU/L

Interpretation

Low Renin - Primary aldosteronism and other mineralocorticoid excess syndromes; "low renin" hypertension; in the aged population.
High Renin - Adrenocortical insufficiency, fluid and salt wasting syndromes; Bartter’s syndrome, severe renal ischaemia, malignant hypertension, renin secreting tumours, and in young children.
Plasma
 Aldosterone-Renin ratio greatly assists interpretation, particularly in primary hyperaldosteronism.

Aldosterone-Renin ratio of >30.5 (pmol/L)/(mIU/L) suggests the presence of primary hyperaldosteronism provided plasma aldosterone exceeds 250 pmol/L and the patient does not have renal failure. Definitive testing (e.g. Saline suppression test) is usually required, under endocrine supervision to confirm the presence of primary hyperaldosteronism. Patient's drugs, posture, volume status and sodium intake all profoundly alter renin levels. Refer to table below for information on how commonly prescribed medication may affect renin and aldosterone levels.

 

Plasma renin

(PRA)

Plasma aldosterone

(PAC)

Aldosterone to renin

(PAC/PRA)

Spironolactone/eplerenone

Diuretics

ACE inhibitors

Angiotensin II RB

Ca blockers(dihydropyridine)

β blockers

Central α2 agonists(clonidine/methyldopa)

Details regarding drug therapy, (including oral contraceptives) and 24 hr urine electrolyte excretion will aid interpretation. Please state time and posture prior to sampling.

Uncertainty of Measurement

1.8mIU/L for <11.4 mIU/L

15.8% for > or equal to 11.4 mIU/L

Additional Information

Plasma must be frozen quickly because prorenin is activated at low (non-frozen) temperatures.

The sooner after bleeding the blood sample can be centrifuged at room temperature and snap frozen, the more reliable the result.

Other protocols involving Renin measurement include frusemide challenge, 2 hours of quiet standing or response to sodium depleting diets. Consult with an Endocrinologist for indications and test protocols.

Delphic Number Test Number8373

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