Lab

Vaginal Fluid Ferning

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Vaginal Fluid Ferning, Ferning

  • Indications
  • Technique
  1. Obtain fluid for exam (usually after Vaginal Pooling)
  2. Place sample on glass slide
  3. Allow sample to air dry for 10 minutes
  • Interpretation
  1. Slide shows Ferning pattern under microscopy
  • Efficacy
  1. Test Sensitivity: 98% when in labor (51% if not in labor)
  2. Test Specificity: 88% when in labor (70% if not in labor)
  • Differential Diagnosis
  1. False positive for Ferning
    1. Cervical Mucus
    2. Semen
  2. False negative for Ferning
    1. Slide not allowed to dry 10 minutes
    2. Swab dry
    3. Contamination with blood