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Lab Manual for Moffitt-Long and Mount Zion

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Fetal Lung Maturity Panel (Lamellar Body Count & Phosphatidyl glycerol)

Item Value
Available Stat? Yes
Test code LBCPGA
Test group Fetal Lung Maturity
Performed by Parnassus Hematology (LBC) and Chemistry (PG)
In House Availability
LBC Test available 24 hours per day 7 days per week
PG Test available day and evening shift only, seven days per week
Method Particle counting by impedance utilizing platelet channel of an automated hematology analyzer (LBC)
Immunoagglutination assay (PG)
Collection Instructions Specify if the specimen has been collected from drainage through the vagina by writing "vaginal pool" on the requisition.

Transport sample immediately to laboratory for testing. If delivery must be delayed or if sending from a remote site refrigerate sample and transport refrigerated.
Container type Red top (preferred) or Plastic tube
Amount to Collect 2 mL Amniotic fluid
Sample type Amniotic fluid
Preferred volume 2 mL Amniotic fluid
Min. Volume 1 mL Amniotic fluid (mat not be sufficient for both assays)
UCSF Rejection Criteria Sample received at room temperature > 1 hour after collection.
Processing notes Do not centrifuge. Deliver immediately to Hematology
Units x109/L
Normal range LBC:
> 50 x 10e9/L Mature
15 - 50 x 10e9/L Transitional
< 15 x 10e9/L Immature


PG:
Present Mature
Stability Refrigerated 5 days
Turn around times Stat: 2 hours, Routine: 4 hours
Additional information Test begins with lamellar body count and if needed based on those results a Phosphatidyl glycerol analysis.

Lamellar body count (LBC) testing employs enumeration of lamellar bodies in amniotic fluid as an index of fetal lung maturity and replaces the surfactant/albumin ratio (S/A ratio), which is no longer commercially available. Numerous studies have demonstrated the clinical performance of the LBC as equal to or better than the S/A ratio.

LBC results are reported as >50 x10e9/L (mature), 15-50 x10e9/L (transitional), and <15 x10e9/L (immature). With mature results, there is a very low risk of respiratory distress syndrome (RDS) of the newborn with delivery. With transitional results, the fetal lungs are probably mature, but the possibility of RDS cannot be excluded. With immature results, the fetal lungs may not be mature and the risk of RDS is significant.

Phosphatidylglycerol (PG) testing will only be performed in cases of transitional LBC results. In samples that are either 'immature' or 'mature' by the LBC assay the PG will be credited.

Note that PG is usually not detectable in significant amounts before 35 weeks gestation. The presence of PG is indicative of fetal lung maturity, however, absence of PG does not necessarily predict development of RDS. Most amniotic fluid samples with LBCs in the transitional range will be negative for PG.

As blood, meconium, and mucous contamination adversely affect the LBC assay, such samples will automatically be submitted to the UCSF Chemistry division for phosphatidylglycerol (PG) testing and the LBC assay will be credited
CPT coding 83664
LDT or Mod FDA? Yes
Last Updated 8/22/2013 4:12:33 PM
Entry Number 1461

If you have additional questions regarding this test, please call: 415-353-1667

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