Interpreting fetal fibronectin test results

Fetal fibronectin (fFN) testing can help you manage preterm birth effectively, without compromising clinical outcomes. The Rapid fFN® test returns either a positive or negative result, enabling you to manage care for your patients accordingly.1


Interpreting negative results


A negative Rapid fFN® test result has a reliably high negative predictive value (NPV) which can help rule out imminent preterm labor.

Negative Test Icon

NPV for delivery within:

7 days = 99.5%
14 days = 99.2%
Less than 37 weeks = 84.5%

A negative Rapid fFN® test result offers benefits that include the opportunity to better manage resources and optimize the administration of steroids.


Interpreting positive results


A positive Rapid fFN® test result indicates that some type of disruption is occurring with the pregnancy.
While only 13% of patients with positive Rapid fFN® test result will deliver in the next 7 days, almost half will deliver before 37 weeks.1

Positive Test Icon

PPV for delivery within:

7 days = 12.7%
14 days = 16.7%
Less than 37 weeks = 44.7%

A positive Rapid fFN® test result offers multiple benefits, including opportunities to better manage care for patients who are at increased risk and optimize administration of steroids.


Interpreting results in asymptomatic patients1


The Rapid fFN® test is also indicated for use in asymptomatic patients during routine prenatal visits between 220 and 306 weeks of gestation in women with a singleton gestation.

In studies on asymptomatic patients:

  • NPVs ranged from 96.4%–97.9% depending on the gestational week of collection, making it highly likely that delivery will not occur before 346 weeks of gestation.
  • PPVs ranged from 13.3%–31.7% and represent an approximate 4- to 7-fold increase in risk over the reliability of predicting delivery in the absence of fFN test information.
  • NPVs and PPVs varied depending on gestational week collected (24, 26, 28, & 30 weeks) and endpoint (286 or 346 weeks).

For more information on asymptomatic testing, see the package insert found here.


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Contact us for more information about the Rapid fFN® test.