Turnaround times
The quoted turnaround time is from sample receipt in the laboratory, to results authorisation in the Laboratory Information Management system. The times do not include transport of specimen to the laboratory or the administrative process to print and post/email reports. Service users must allow for transport and reporting time when ordering tests.
Clinical background:
Clinical utility
Metanephrines are measured in urine for the biochemical diagnosis and monitoring of phaeochromocytoma and functional paraganglioma.
Clinical significance
Phaeochromocytoma and functional paraganglioma are rare neuroendocrine tumours that are characterised by excessive secretion of catecholamines. With such low disease prevalence, initial biochemical testing should reliably exclude or confirm the presence of a catecholamine-secreting tumour. Measurement of free (unconjugated) metanephrines in plasma has been shown to be a highly sensitive test for the detection of phaeochromocytoma. With a diagnostic sensitivity of 98% and specificity of 92%, a negative test result virtually rules out the diagnosis.
Specimen container paediatric:
- Brown 24h urine container:
- With the addition of 20 g of sand and 6 mL of sulphuric acid (4 mol/L).
Specimen container adult:
- Brown 24h urine container:
- With the addition of 20 g of sand and 6 mL of sulphuric acid (4 mol/L).
Minimum volume paediatric:
1 – 10 mL urine
Minimum volume adult:
1 – 10 mL urine
Special requirements:
Do
- Upon receipt in laboratory, adjust pH to 3.0 to 6.0, and remove an aliquot for analysis.
- Store urine aliquot at 4°C prior to transport and analysis.
Do not
- over-acidify to pH <3.0
Sample stability:
- Once pH has been adjusted to 3.0 to 6.0, samples are stable at 4°C for up to 10 days.
- For long-term storage, store samples at –20°C.
Transport requirements:
For external laboratories:
Once pH has been adjusted to 3.0 to 6.0, transport urine aliquot at ambient temperature.
Freq Analysis:
1 x weekly
Quality assurance:
UK NEQAS
Interpretation:
Urine metanephrine or normetanephrine values greater than 3 times the upper reference interval are highly suggestive of the presence of phaeochromocytoma/paraganglioma.
Reference ranges:
| Age | Metanephrine (µmol/24h) | Normetanephrine (µmol24h) | 3-methoxytyramine (µmol/24h) |
| 0 to 9 months | 0 – 0.2 | 0.2 – 0.8 | N/A |
| 9 to 12 months | 0 – 0.5 | 0.1 – 0.6 | N/A |
| 1 to 2 years | 0 – 0.3 | 0.2 – 0.6 | N/A |
| 2 to 6 years | 0.1 – 0.5 | 0.3 – 0.6 | N/A |
| 6 to 10 years | 0.3 – 0.7 | 0.3 – 1.0 | N/A |
| 10 to 16 years | 0.2 – 1.2 | 0.3 – 1.6 | N/A |
| Adults (female) | 0 – 1.8 | 0 – 3.0 | 0 – 2.8 |
| Adults (male) | 0 – 2.2 | 0 – 3.8 | 0 – 2.8 |
Other Info:
Urine metanephrines analysis is performed by LC-MS/MS.