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45150:FETAL LUNG MATURITY CASCADE | |||||||||
Methodology: | S/A Ratio: Fluorescent Polarization Immunoassay (FPIA); L/S & PG: Thin Layer Chromatography with Cupric Acetate Charring | ||||||||
Edit Date: | 1/3/2007 | ||||||||
Performed: | Daily at 1300 (STAT 800) | ||||||||
Released: | Results at 1700 (STAT at 1300) | ||||||||
CPT Code: | 83663 | ||||||||
Specimen Collection Details | |||||||||
Collection: | 7.5 mL amniotic fluid. | ||||||||
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-top 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, 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.
The S/A ratio is done first and resulted within 45 minutes after specimen receipt in department. If S/A ratio is mature, testing stops; the L/S and PG will not be performed. If the S/A ratio is immature, L/S and PG testing will be performed on the next run. |
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Rejection Criteria: | Vaginal specimen too mucoid to pipette. |