title: The predictive value of urinary vanillylmandelic acid testing in the diagnosis of phaeochromocytoma at the University Hospital of the West Indies.
abstract: OBJECTIVE
  To investigate the positive predictive value (PPV) of urinary vanillylmandelic acid (VMA) testing in the diagnosis of phaeochromocytoma and to describe the features associated with phaeochromocytoma at the University Hospital of the West Indies (UHWI).
  
  
  METHODS
  There were 551 VMA tests performed from January 2003 to June 2009 and 122 tests in 85 patients were elevated (ie > or = 35 micromol/24 hr). The study patients were categorized as: (i) 'surgical' (5 patients who underwent surgery) or (ii) 'non-surgical' (remaining 80 patients). Forty medical charts (out of 85) were reviewed using a standardized data extraction form.
  
  
  RESULTS
  The median age for patients in the non-surgical group (with charts reviewed, n = 35) was 36 years (range 9-70) and the median VMA was 43 micromol/24 hr (IQR 38-51). Of these patients, 83% had one or no symptom typical of phaeochromocytoma. In the surgical group the median VMA was 58 micromol/24 hr (IQR 44-101); phaeochromocytoma was confirmed histologically in 3 patients, all of whom had several symptoms typical of catecholamine excess. VMA testing had a PPV of 8%, specificity of 79% and sensitivity of 100%.
  
  
  CONCLUSIONS
  VMA testing at UHWI has poor specificity and high sensitivity. These results contrast with international data showing that VMA testing is poorly sensitive but highly specific. The use of assays with higher specificity (eg plasma or urinary metanephrines) may represent a more cost-effective approach to biochemical screening at UHWI.
authors.affiliation: Department of Medicine, The University of the West Indies, Kingston 7, Jamaica, West Indies.
authors.forename: S N
authors.initials: SN
authors.lastname: Chin
authors.forename: M S
authors.initials: MS
authors.lastname: Boyne
authors.forename: D
authors.initials: D
authors.lastname: McGrowder
authors.forename: T N
authors.initials: TN
authors.lastname: Gibson
authors.forename: C A
authors.initials: CA
authors.lastname: McKenzie
mesh_terms: D000293:Adolescent; D000310:Adrenal Gland Neoplasms / Q000175:diagnosis* / Q000601:surgery; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000652:urine; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010673:Pheochromocytoma / Q000175:diagnosis* / Q000601:surgery; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014642:Vanilmandelic Acid / Q000652:urine*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D014642:Vanilmandelic Acid