title: Prospective evaluation of the saline infusion test for excluding primary aldosteronism due to aldosterone-producing adenoma.
abstract: BACKGROUND
  Data on the performance of the tests used to confirm the diagnosis of primary aldosteronism (PA) are limited.
  
  
  OBJECTIVE
  To prospectively investigate the accuracy of the saline infusion test (SIT).
  
  
  METHODS
  Three hundred and seventeen (26.9%) out of 1125 patients screened in the PAPY study underwent measurement of plasma aldosterone, cortisol and renin activity after infusion of 2 l of isotonic saline intravenously over 4 h. They comprised patients with a baseline aldosterone/renin ratio (ARR) > 40 and one every four patients not fulfilling such criterion. The area under the receiver-operator characteristic curves (AUC) of aldosterone values after SIT was used as a measure of accuracy for diagnosing PA, aldosterone-producing adenoma (APA) or idiopathic hyperaldosteronism (IHA).
  
  
  RESULTS
  One hundred and twenty (37.9%) patients had PA that was due to an APA in 46 (38.3%) and to IHA in 74 (61.7%). No untoward effect occurred with the SIT. The AUC (0.811 +/- 0.026, 0.878 +/- 0.040 and 0.784 +/- 0.034 for identification of PA, APA and IHA, respectively) was higher (P < 0.0001) than that under the diagonal. By sensitivity/specificity versus criterion values plot, the best aldosterone cut-off values for identifying APA and IHA were 6.75 and 6.91 ng/dl, respectively. However, even at these optimal cut-offs, sensitivity and specificity were moderate because of values overlapping between patients with and without the disease. Moreover, there were no differences of AUC and aldosterone cut-offs between APA and IHA.
  
  
  CONCLUSIONS
  In a multicenter study the SIT was safe and specific for excluding PA, but had no place for discriminating between an APA and IHA.
authors.affiliation: DMCS-Clinica Medica 4, University Hospital, Padova, Italy. gianpaolo.rossi@unipd.it
authors.forename: Gian Paolo
authors.initials: GP
authors.lastname: Rossi
authors.forename: Anna
authors.initials: A
authors.lastname: Belfiore
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Bernini
authors.forename: Giovambattista
authors.initials: G
authors.lastname: Desideri
authors.forename: Bruno
authors.initials: B
authors.lastname: Fabris
authors.forename: Claudio
authors.initials: C
authors.lastname: Ferri
authors.forename: Gilberta
authors.initials: G
authors.lastname: Giacchetti
authors.forename: Claudio
authors.initials: C
authors.lastname: Letizia
authors.forename: Mauro
authors.initials: M
authors.lastname: Maccario
authors.forename: Francesca
authors.initials: F
authors.lastname: Mallamaci
authors.forename: Massimo
authors.initials: M
authors.lastname: Mannelli
authors.forename: Domenico
authors.initials: D
authors.lastname: Montemurro
authors.forename: Gaetana
authors.initials: G
authors.lastname: Palumbo
authors.forename: Damiano
authors.initials: D
authors.lastname: Rizzoni
authors.forename: Ermanno
authors.initials: E
authors.lastname: Rossi
authors.forename: Andrea
authors.initials: A
authors.lastname: Semplicini
authors.forename: Enrico
authors.initials: E
authors.lastname: Agabiti-Rosei
authors.forename: Achille Cesare
authors.initials: AC
authors.lastname: Pessina
authors.forename: Franco
authors.initials: F
authors.lastname: Mantero
mesh_terms: D000236:Adenoma / Q000097:blood* / Q000473:pathology; D000310:Adrenal Gland Neoplasms / Q000097:blood* / Q000473:pathology; D000450:Aldosterone / Q000097:blood*; D003937:Diagnosis, Differential; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D006929:Hyperaldosteronism / Q000097:blood / Q000150:complications / Q000175:diagnosis*; D006973:Hypertension / Q000097:blood / Q000175:diagnosis / Q000209:etiology; D007262:Infusions, Intravenous; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D012083:Renin / Q000097:blood; D015203:Reproducibility of Results; D012965:Sodium Chloride / Q000008:administration & dosage
chemical_list: D012965:Sodium Chloride; D000450:Aldosterone; D012083:Renin; D006854:Hydrocortisone