If 'catecholamines' are requested, please collect for 'metanephrines' unless you are aware of prior consultation between a pathologist and the requesting doctor with a decision to specifically collect catecholamines.
If catecholamines are to be collected, blood must be added to 7 mL lithium heparin no gel tube containing 2-3 mg sodium metabisulphate (do not put in excess amounts of metabisulphate as this haemolyses the specimen; ensure that less than 10 mg is added). Tubes can be obtained prior to collection from Biochemistry (will need to be made up by one of the Biochemistry staff). These additive tubes are stable in the refrigerator for 12 months from the date of preparation.
Patient must be lying down during the procedure and an indwelling cannula must be inserted and left for 30 minutes prior to collection. Insert an IV line, attach a 3-way tap, then collect blood 30 mins after insertion of the cannula. Sampling via a syringe will be necessary for this additive tube.
Patient must be calm during collection.
The sample must arrive in the laboratory on a cold pack within 90 minutes of collection.
Pre-prepared tubes are kept in refrigerator Specialist Clinics collection area and more should be requested from Clinical Chemistry when the last 2 are taken.
If 'catecholamines' are requested 'metanephrines' (metadrenaline and normetadrenaline) will be measured. If adrenaline and/or noradrenaline are specifically required, please contact a Chemical Pathologist on 3163 8607 to arrange the appropriate collection.
INTERPRETATION: Elevated levels suggest the presence of phaeochromocytoma or paraganglioma. If clinical uncertainity exists and the tumour cannot be located by diagnostic imaging, a clonidine suppression test may be indicated.