Soluble Fms-like tyrosine kinase-1(sFlt-1) and Placental growth factor (PlGF)

Diagnostic Use

sFlt-1 and PlGF are used to determine the ratio of sFlt-1/PLGF. The sFlt-1/PlGF ratio is a biomarker of placental insufficiency, and has proven clinical benefit as a rule-out test for pre-eclampsia. Similarly, an elevated ratio is associated with placental insufficiency and may contribute towards a diagnosis of pre-eclampsia in patients with supporting clinical and/or biochemical features of the condition.

Used as a pre-eclampsia marker for women >20 weeks gestation with:
• Suspected pre-eclampsia
• Isolated or worsening hypertension
• Isolated or worsening proteinuria
• Isolated fetal growth restriction

Department

Endocrinology Lab

Delphic Registration Code

SFPG

Synonyms

sFlt-1, PlGF

Turnaround Time

3 days

Test Code

SFPG

Specimen Type

• Serum

Specimen Requirements

Tube/Container Type:

Preferred

• Serum (Red Cap)
• SST II (Gold Cap)

Acceptable

• Serum (Red Cap)
• SST II (Gold Cap)

Preferred Sample Volume (ml)

2

Minimum Sample Volume (ml)

1

No of Samples Required

1

Additional Specimen Information

Turnaround time: 3hours routinely Mon-Fri between 9am-3pm. For urgent requests between 3pm-5pm, please phone the laboratory on x80885 otherwise testing will take place on the next weekday. This test is not available out-of-hours.
Performed by Endocrinology laboratory

Aliquot Instructions

Sample Type

• Serum

Minimum Volume (ml)

1

Transport to Lab

Ambient (8 - 24 degrees Celsius)

Additional Referral/Aliquot Information

If analysis is to take place within 48hrs of collection, storage and transport at 2-8°C is acceptable. Serum should be frozen if there is likely to be a delay of >48hrs between collection and analysis.

Interpretation

The sFlt-1/PlGF ratio is interpreted according to gestational age, as per the table below:

Ratio	Gestation
≤38	>20+0	sFlt-1/PlGF ratio is in the normal range.  The probability of developing pre-eclampsia in the next seven days is low.
38-84	20+0 to 33+6	Consistent with placental dysfunction, and a higher risk of adverse pregnancy outcome.
38-109	34+0 to 36+6
≥85	20+0 to 33+6	Consistent with severe placental dysfunction.  In cases of suspected pre-eclampsia, this result is considered confirmatory.
≥110	34+0 to 36+6

 

 

Reference Intervals

Results >38 will be flagged as abnormal

See above table for more information on interpretation.

 

References:

Hughes, R et al; The predictive value of the sFlt-1/PlGF ratio in suspected pre-eclampsia in a New Zealand population: A prospective cohort study. Aust NZ J Obstet Gynaecol 2022: 1-8

Test Method

Roche Electrochemiluminescence immunoassay

Non-Funded Test Cost

$318 (Exclusive of GST)

Billing Code

2750

Please fully complete the dedicated sFlt-1/PlGF ratio request form.
Testing will not take place unless a gestational age is provided. This test is not valid for pregnancies less than 20 weeks’ gestation.
This test is for request by obstetric specialist only.

Resources

• sFlt-1 PlGF Ratio Request Form (34 KB)

Contact Information

Enquiry Form