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Order Code LS RATIO FMUC Lecithin/Sphingomyelin (L/S) Ratio and Phosphatidylglycerol (PG), Amniotic Fluid

Specimen Requirements

Specimen must arrive and be processed within 4 hours of collection. Notify Ridgeview Medical Center Laboratory at 952-442-2191, extension 5600 to let them know specimen is coming.

 

8 mL of unprocessed amniotic fluid. Send specimen refrigerated in a plastic, leakproof vial.

Note:  1. Include “tap or pool,” “diabetic or nondiabetic,” and weeks gestation on request form.

2. Label vial with patient’s name, date of birth or hospital medical record number, specimen source, date and time of collection, and collector’s initials.

Reference Values

L/S ratio <2.0 indicates immature lungs; a ratio of 2.0-3.0 indicates borderline mature lungs; and a ratio >3.0 indicates mature lungs. Infants of diabetic mothers have an increased risk of developing respiratory distress syndrome when L/S ratio indicates borderline mature or mature lungs but PG is not present. In the presence of PG, the incidence of respiratory distress syndrome is very low (<0.5%) for all infants.

Day(s) Test Set Up

Monday through Friday

Performing Laboratory

Fairview University Medical Center (FUMC)

Methodology

Thin-Layer Chromatography (TLC)/Densitometry

Test Classification and CPT Coding

83361-Fetal lung maturity assessment; L/S ratio

84081-PG