Fetal Fibronectin

(fFN)

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Definition

-  Detection of fetal fibronectin in cervico-vaginal fluid during pregnancy to determine liklehood of preterm labour

 

Features

-  Simple reliable antibody reagent test

-  Unique glycosolated form of plasma protein fibronectin

-  Found in placenta & amniotic fluid (uteroplacental junction)

-  Released into upper vagina near onset of labour

-  High negative predictive value

-  Tested on cervico-vaginal fluid

 

Indications

-  Threatened pre-term labour to determine need for medical admission &/or transfer

-  Intact membranes

-  Cervical dilation <3cm

-  Nil or minimal vaginal bleeding, placenta previa, placental abruption

-  No intercourse in last 24hrs (false positives)

-  No VE in last 24hrs (false positives)

-  If maternity unit/nursery not able to manage delivery at current gestation provides assistance in decision to transfer to higher level maternity unit

 

Equipment

-  Speculum

-  Sterile gloves

-  No lubricant

-  Fetal Fibronectin Quick Check Kit

-  Applicator

-  Test tube (extraction buffer)

-  Test strip

 

 

Procedure

-  Speculum examination without lubrication (may invalidate test)

-  Avoid touching cervix w spec

-  Insert applicator tip to posterior fornix of vagina & rotate for 10sec

-  Remove applicator & insert into test tube with buffer

-  Mix vigorously for 10-15sec

-  Discard applicator

-  Insert test strip into buffer for exactly 10min

-  Remove test strip & read results

 

Results

-  Negative

-  1 distinct line: control line (no test line)

-  97-99% chance of not progressing to labour in next 7 days

-  Positive

-  2 lines: control + test line (irrespective of how dark)

-  15-25% chance of progressing to labour

-  Admit &/or arrange transfer to hight level maternity unit if needed

-  24-34 weeks gestation: Corticosteroids (Celestone 11.4mg IM x2 24hrs apart) for foetal lung maturation

-  Invalid

-  No control line w or wo test line

 

 

 

 

References

 

Southern Health CPG: Fetal Fibronectin Quick check test in Threatened Preterm Labour Guideline, August 2009

Info + Pic (Quick Check + Results): www.ffntest.com/hcp/testing/quikcheck.html