Plasma chromogranin A or urine fractionated metanephrines follow-up testing improves the diagnostic accuracy of plasma fractionated metanephrines for pheochromocytoma.
J Clin Endocrinol Metab
; 93(1): 91-5, 2008 Jan.
Article
en En
| MEDLINE
| ID: mdl-17940110
ABSTRACT
CONTEXT The initial diagnosis of pheochromocytoma relies on plasma fractionated metanephrines levels. Normal levels exclude pheochromocytoma, but positive tests have a low positive predictive value due to the disease's rarity. OBJECTIVES:
The objective of the study was to evaluate three approaches to distinguish between true-positive and false-positive tests 1) increased cutoff for plasma fractionated metanephrines, 2) measurement of serum/plasma chromogranin A (CGA), and 3) urine fractionated metanephrine testing.DESIGN:
We studied retrospectively all Mayo Clinic patients with positive plasma fractionated metanephrine tests over a 15-month period and determined their final diagnosis based on histology, imaging, additional biochemical tests, and more than 1 yr follow-up. For a subgroup, urine fractionated metanephrine results were available. All original plasma samples were retested for CGA.RESULTS:
Of 140 patients, 40 had a chromaffin tumor confirmed and 100 excluded, indicating a positive predictive value of plasma fractionated metanephrines of 28.6%. Increasing the threshold for a positive test improved specificity to 98% but missed eight cases (20%). Incorporation of urine fractionated metanephrine testing as follow-up test achieved 80% specificity and 91% sensitivity. The corresponding figures for CGA were 71 and 87% for all patients and 89 and 87% when patients taking proton pump inhibitors were excluded.CONCLUSIONS:
Unless plasma fractionated metanephrines levels are elevated more than 4-fold above the upper limit of normal, patients with a positive plasma fractionated metanephrines test should be evaluated with urine fractionated metanephrines and serum/plasma CGA assays before being subjected to imaging or invasive diagnostic tests.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Feocromocitoma
/
Metanefrina
/
Neoplasias de las Glándulas Suprarrenales
/
Cromogranina A
Tipo de estudio:
Diagnostic_studies
/
Etiology_studies
/
Incidence_studies
/
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Límite:
Female
/
Humans
/
Male
/
Middle aged
País/Región como asunto:
America do norte
Idioma:
En
Revista:
J Clin Endocrinol Metab
Año:
2008
Tipo del documento:
Article
País de afiliación:
Estados Unidos