Serum metanephrines

Investigation Protocol

Indication

Screening of patients with suspected phaeochromocytoma, usually following positive or borserline urinary metanephrines. 

Preparation

The patient can eat and drink, and take their medications as usual, but are asked to bring them all in with them for documentation. Caffeine and cigarettes should be avoided for four hours, and all over the counter medicines should be avoided for 48 hours before the test, as paracetamol can cross react with assays, and cough medicines may contain sympathomimetics.

Protocol

The patient should be cannulated and then lie resting 15 minutes prior to performing the test. Blood should then be taken into an EDTA tube, and immediately centrifuged, separated and the plasma frozen, labelled with the patient details, date and time, to be sent for analysis.

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Patient information sheet

Serum metanephrines 

Your doctor has asked us to coordinate a blood test to measure some very specialised hormones, which are produced in glands called the adrenals. Too much of these hormones can affect your blood pressure and may give you symptoms such as anxiety.

We will be inserting a small tube (a cannula) into a vein in your arm after which you will be allowed to rest for 20 minutes before we take the blood sample. This is because the hormones we are measuring are stress hormones and so need to be taken in a resting patient. The samples also need to be handled in a specific way after they are taken, so unfortunately you cannot have this done in outpatients or at your GP surgery.

Please eat and drink normally and take all your medication as normal on the day of this test. However, we do ask that you avoid cough mixtures and paracetamol for 48 hours prior to the test, and avoid caffeine containing drinks such as tea, coffee and cola for four hours before it.

Unless you have already done so, we may also need you to perform two 24 hour urine collections for us after this test. If this is also needed we will provide you with the urine canisters when you come up to the unit with written instructions of what to do.

You should expect your stay at the hospital to be about 30-45 minutes. You may wish to bring a book or magazine to read. We do have a radio, or you can access Patientline; alternatively you may like to bring your own personal radio/cd player (please bring your own headphones). You may bring someone to stay with you during the test but there is not enough space for more than one person.

Children are discouraged, as this can be disruptive to other patients. However, if this poses a particular problem for you please discuss this with the senior nurse in the unit. You should be able to undertake normal activities after the test is finished and it should not interfere with your ability to drive home. 

If you have any queries about the test, please contact: 

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