title: Combination of the Schirmer I and phenol red thread tests as a rescue strategy for diagnosis of ocular dryness associated with Sjögren's syndrome.
abstract: OBJECTIVE
  To define a combination of the Schirmer I and phenol red thread (PRT) tests that improves the screening of patients with ocular sicca syndrome.
  
  
  METHODS
  The PRT test was performed before (PRT1) and after (PRT2) the Schirmer I test, in both eyes of 143 patients complaining of ocular dryness secondary to Sjögren's syndrome or sicca asthenia polyalgia syndrome (SAPS; 72 and 71 patients, respectively), and in 40 control patients. Groups were matched by age and sex. After determining the best cutoff values using the receiver operating characteristic procedure, several combinations of PRT and Schirmer I were assessed to improve the predictive values of the procedure.
  
  
  RESULTS
  The best cutoff value for PRT2, estimated at 15 mm, provided a satisfying match between sensitivity and specificity indexes (68% and 90%, respectively), similar to those obtained with the Schirmer I test. If PRT1 alone was ineffective to screen SGS from control patients, the comparison between PRT1 and PRT2 (so-called "DeltaPRT") was found as a good marker to detect patients with persistent tear reflex. Interestingly, the combination of positive Schirmer I, PRT 2, and/or ΔPRT tests was found to be highly predictive of severe ocular sicca syndrome.
  
  
  CONCLUSIONS
  The combination of the Schirmer I and PRT tests strongly improves the screening procedure to detect patients with ocular dryness related to Sjögren's syndrome or SAPS. It could be more widely used in daily clinical practice, aside from the Schirmer I test, to optimize the work-up of patients presenting with dry-eye subjective signs.
authors.affiliation: Department of Ophthalmology, Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, Université Paris Sud, Le Kremlin-Bicêtre Cedex, France.
authors.forename: Ivan
authors.initials: I
authors.lastname: de Monchy
authors.forename: Gaël
authors.initials: G
authors.lastname: Gendron
authors.forename: Corinne
authors.initials: C
authors.lastname: Miceli
authors.forename: Nicolas
authors.initials: N
authors.lastname: Pogorzalek
authors.forename: Xavier
authors.initials: X
authors.lastname: Mariette
authors.forename: Marc
authors.initials: M
authors.lastname: Labetoulle
mesh_terms: D004396:Coloring Agents; D003941:Diagnostic Techniques, Ophthalmological / Q000592:standards; D015352:Dry Eye Syndromes / Q000175:diagnosis* / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010637:Phenolsulfonphthalein; D011237:Predictive Value of Tests; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012859:Sjogren's Syndrome / Q000150:complications*; D013666:Tears / Q000378:metabolism
chemical_list: D004396:Coloring Agents; D010637:Phenolsulfonphthalein