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Test Code FERN Fern Test

Additional Codes

Cerner

NextGen

Fern Test

Amniotic Fluid Crystallization Test

Alternate Name(s)

Amniotic Fluid Crystallization Test

Methodology

Microscopy

Patient Preparation

None

Collection Instructions

See Fern Test Collection Instructions for detailed collection instructions.

  • The specimen is collected by the physician from posterior vaginal pool with a sterile swab.  DO NOT touch the mucous plug in the cervix. If the collection swab is compromised for any reason, obtain a new swab for collection of specimen.
  • After collection, immediately rub the swab against a glass slide, creating a very thin smear.
  • Do not cover slip the slide.  Allow the slide to air dry.  Do Not Apply heat.
  • The specimen is labeled with patient name, date and medical records number and submitted to the laboratory department with an order in computer for Fern Test.

Specimen Requirements

Container

Physician and/or nurse prepared microscope slides.

Stability

Not Defined

Rejection Criteria

Not Defined

Result Reporting and Reference Values

Reference Range

Negative for Ferning

Critical Ranges

None

Reflex Testing

None

Limitations

  • False positive results may occur from specimens contaminated with blood, urine or cervical mucous.
  • False negative results may occur from prolonged rupture of the membranes (longer than 24 hours).
  • False negative results may occur if only a small volume of fluid has leaked.
  • Nursing or physician may review the slide in the lab also.  Nursing policy states that the nurse will contact the physician if a discrepancy in results occurs.