Preanalytical validation and reference values for a mass spectrometric assay of serum vanillylmandelic acid for screening of catecholamine secreting neuroendocrine tumors.
Clin Chim Acta
; 446: 206-12, 2015 Jun 15.
Article
em En
| MEDLINE
| ID: mdl-25896957
ABSTRACT
BACKGROUND:
Urinary vanillylmandelic acid (VMA) is used to diagnose and monitor catecholamine secreting neuroendocrine tumors (NETs). We developed and validated a new liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for determination of serum VMA.METHODS:
We used serum samples from healthy volunteers (n=314) and patients suspected for NET (n=36). Deuterated VMA as an internal standard was added to samples before solid phase extraction (SPE) and LC-MS/MS analysis. We studied the effects of sample storage, sampling device and a meal on serum VMA and metanephrine concentrations. Diurnal variation and age-dependent reference intervals were established. The diagnostic performance was compared with a urinary HPLC assay for VMA and metanephrines and a serum metanephrine LC-MS/MS assay.RESULTS:
Serum VMA is stable at least for one day at +4°C, seven days at room temperature and 98 days at -20°C. Type of sampling device was not critical, but elevated serum VMA occurs after a meal (p = 0.031). Serum VMA increased with age. Therefore, we suggest clinical cut-off values of 62 nmol/L, 80 nmol/L and 108 nmol/L for age groups 18-50 yrs, 51-70 yrs and > 70 yrs, respectively. Comparison between a urinary VMA HPLC assay and serum VMA LC-MS/MS assay showed good correlation.CONCLUSIONS:
Our LC-MS/MS assay is fast and sensitive and suits well for use in a clinical laboratory. Compared to 24-h urine collection our serum assay enables well controlled sampling and convenient preanalytical steps.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Paraganglioma
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Ácido Vanilmandélico
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Bioensaio
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Biomarcadores Tumorais
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Adenoma
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Neoplasias das Glândulas Suprarrenais
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Neuroblastoma
Tipo de estudo:
Diagnostic_studies
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Observational_studies
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Screening_studies
Limite:
Adolescent
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Adult
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Aged
/
Female
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Humans
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Male
/
Middle aged
Idioma:
En
Revista:
Clin Chim Acta
Ano de publicação:
2015
Tipo de documento:
Article