title: Urine Test Strips as a Bedside Diagnostic Aid to Rule out Blood in CSF: A Validation.
abstract: BACKGROUND
  Patients presenting to the emergency department with acute-onset, atypical headaches require an evaluation for subarachnoid hemorrhage (SAH). The standard evaluation for SAH includes noncontrast computed tomography of the head and, if negative, a lumbar puncture to determine the presence of blood in the cerebrospinal fluid (CSF). In austere environments without full laboratory capabilities, a rapid bedside diagnostic test allowing clinicians to rule out SAH would reduce costly transfers of patients requiring further evaluation. CSF samples obtained while evaluating patients for potential SAH were tested with the blood panel of Bayer Multistix urine test strips.
  
  
  METHODS
  We compared the test strip color change to the number of red blood cells per high power field found on laboratory analysis of the CSF.
  
  
  RESULTS
  The sensitivity of the Multistix for detecting red blood cells in the CSF was 100%, with a specificity of 56%. The positive predictive value was 37%, and the negative predictive value was 100%.
  
  
  CONCLUSIONS
  These results are encouraging and may form the basis for potential use of urine test strips as a tool to rule out subarachnoid blood in austere environments, but the test strips' low specificity limits their usefulness as a practical clinical tool at this time.
authors.affiliation: Department of Emergency Medicine, Walter Reed National Military Medical Center, 8901 Rockville Pike, Bethesda, MD 20889.
authors.forename: Shannon F
authors.initials: SF
authors.lastname: Reeve
authors.affiliation: Department of Emergency Medicine, Naval Hospital Camp Lejeune, 100 Brewster Boulevard, Camp Lejeune, NC 28547.
authors.forename: Jamie S
authors.initials: JS
authors.lastname: Johnson
authors.affiliation: Department of Emergency Medicine, Naval Medical Center Portsmouth, 620 John Paul Jones Circle, Portsmouth, VA 23708.
authors.forename: Robin
authors.initials: R
authors.lastname: Marshall
mesh_terms: D000328:Adult; D002555:Cerebrospinal Fluid / Q000166:cytology*; D004636:Emergency Service, Hospital; D006261:Headache / Q000209:etiology; D006417:Hematuria / Q000175:diagnosis; D006801:Humans; D000067716:Point-of-Care Testing; D011934:Reagent Strips; D012680:Sensitivity and Specificity; D013129:Spinal Puncture; D013345:Subarachnoid Hemorrhage / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000652:urine; D014057:Tomography, X-Ray Computed
chemical_list: D011934:Reagent Strips