Preanalytical Considerations and Outpatient Versus Inpatient Tests of Plasma Metanephrines to Diagnose Pheochromocytoma.

Abstract

CONTEXT:

Sampling of blood in the supine position for diagnosis of pheochromocytoma and paraganglioma (PPGL) results in lower rates of false positives for plasma normetanephrine than seated sampling. It is unclear how inpatient vs outpatient testing and other preanalytical factors impact false positives.

OBJECTIVE:

We aimed to identify preanalytical precautions to minimize false-positive results for plasma metanephrines.

METHODS:

Impacts of different blood sampling conditions on plasma metanephrines were evaluated, including outpatient vs inpatient testing, sampling of blood in semi- vs fully recumbent positions, use of cannulae vs direct venipuncture, and differences in outside temperature. A total of 3147 patients at 10 tertiary referral centers were tested for PPGL, including 278 with and 2869 without tumors. Rates of false-positive results were analyzed.

RESULTS:

Outpatient rather than inpatient sampling resulted in 44% higher plasma concentrations and a 3.4-fold increase in false-positive results for normetanephrine. Low temperature, a semi-recumbent position, and direct venipuncture also resulted in significantly higher plasma concentrations and rates of false-positive results for plasma normetanephrine than alternative sampling conditions, although with less impact than outpatient sampling. Higher concentrations and rates of false-positive results for plasma normetanephrine with low compared with warm temperatures were only apparent for outpatient sampling. Preanalytical factors were without impact on plasma metanephrines in patients with PPGL.

CONCLUSION:

Although inpatient blood sampling is largely impractical for screening patients with suspected PPGL, other preanalytical precautions (eg, cannulae, warm testing conditions) may be useful. Inpatient sampling may be reserved for follow-up of patients with difficult to distinguish true- from false-positive results.

• Authors: Georg Pommer, Christina Pamporaki, Mirko Peitzsch, Hanna Remde, Timo Deutschbein, Svenja Nölting, Lisa Marie Müller, Leah Braun, Sven Gruber, Alessio Pecori, Stephanie Hampson, Eleanor Davies, Anthony Stell, Gian Paolo Rossi, Livia Lenzini, Filippo Ceccato, Henri J L M Timmers, Jaap Deinum, Laurence Amar, Anne Blanchard, Stephanie Baron, Martin Fassnacht, Piotr Dobrowolski, Andrzej Januszewicz, Maria-Christina Zennaro, Aleksander Prejbisz, Graeme Eisenhofer
• Journal: The Journal of clinical endocrinology and metabolism (J Clin Endocrinol Metab) Vol. 107 Issue 9 Pg. e3689-e3698 (08 18 2022) ISSN: 1945-7197 [Electronic] United States
• PMID: 35767279 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © The Author(s) 2022. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: [email protected].

Chemical References

• Normetanephrine
• Metanephrine

Topics

• Adrenal Gland Neoplasms (pathology)
• Humans
• Inpatients
• Metanephrine
• Normetanephrine
• Outpatients
• Paraganglioma (pathology)
• Pheochromocytoma (pathology)
• Sensitivity and Specificity