Test Overview
Test Methodology

Thin-Layer Chromotography

Test Usage

Amniotic fluid test for fetal maturity, indicator to determine optimal time for obstetrical intervention in cases of possible fetal distress (maternal diabetes, toxemia, isoimmune hemolytic disease, postmaturity).

Reference Range *

IMMATURE: L/S <2.5, Phosphatidylglycerol Absent; INDETERMINATE: L/S >=2.5, Phosphatidylglycerol Absent or L/S <2.5, Phosphatidylglycerol Trace; MATURE: L/S >=2.5, Phosphatidylglycerol Trace or L/S Any Ratio, Phosphatidylglycerol Present.

Test Details
Days Set Up
Monday - Saturday
Analytic Time

2 - 3 days

Soft Order Code
  • Phosphatidylglycerol (PG)
  • Lecithin/Sphingomyelin Ratio
  • Lecithin / Sphingomyelin Ratio
  • Phosphatatidylglycerol
  • Fetal Lung Maturity
  • L/S Ratio
Reference Laboratory
Mayo FLP (8929)
Special Testing
Specimen Requirements
Collection Instructions

Collect amniotic fluid. Centrifuge at 1000 rpm or 200 x G for 10 minutes, aliquot supernatent into a plastic tube and send both supernatent and sediment frozen. Label specimens appropriately, "supernatent" and "sediment". Include estimated duration of pregnancy (in weeks).

L/S ratio is not indicated if FLM is > or = 55 mg/gm.
Normal Volume
10 mL amniotic fluid
Minimum Volume
3 mL amniotic fluid
Additional Information

Test includes Lecithin/Sphingomyelin (L/S) ratio and phosphatidylglycerol. Test sent to Mayo Medical Laboratories.

CPT Code
83661 L/S Ratio, 84081 Phosphatidylglycerol
Fee Code
NY State Approved