Results at 1700 (STAT at 1300). S/A Ratio results within 1-2 hours of receipt in laboratory.
CPT Code:
83661 / 83663 / 84081
Specimen Collection Details
Collection:
7.5 mL amniotic fluid. If sample is insufficient for more than one test, indicate preferred test to be performed.
Handling:
Pour off minimum 1.5 mL unspun amniotic fluid and label ‘unspun’. Centrifuge remainder of specimen for 3 minutes at 1700 rpm (lower than routine centrifuging). Transfer supernatant to a plastic screw-cap vial and label ‘spun.’ Refrigerate. Include additional clinical information on requisition, i.e., weeks gestation, is patient diabetic, source if not amniotic fluid, e.g., vaginal pool.
Stability:
24-36 hours refrigerated, or 14 days frozen.
Standard Volume:
7.5 mL amniotic fluid.
Minimum Volume:
1 mL amniotic fluid for S/A ratio, 2.5 mL for L/S ratio, and 1.5 mL for PG.
Transport:
Refrigerated if received in laboratory within 36 hours, or frozen on dry ice if transport is delayed.
Comments:
Visible meconium or blood greater than 2% Hct may interfere with the S/A and L/S ratio.
Rejection Criteria:
Vaginal specimens that are mucoid and difficult to pipette.
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