Mayo Test Catalog, (Sorted By Test Name) - Mayo Medical ...

LBCR
61179
LBC
60450
Clinical References: Homburger HA: Allergic diseases. In Clinical Diagnosis and Management
by Laboratory Methods. 21st edition. Edited by RA McPherson, MR Pincus. New York, WB Saunders
Company, 2007, Chapter 53, Part VI, pp 961-971
Lamellar Body Count Reflex, Amniotic Fluid
Clinical Information: Fetal lung maturity testing is used to determine the risk for developing
respiratory distress syndrome (RDS) in infants born prematurely (32-39 weeks). The risk for developing
RDS is inversely related to gestational age and is the most common cause of respiratory failure in
neonates. RDS is associated with preterm birth due to insufficient production of pulmonary surfactant.
Pulmonary surfactant is synthesized by type II pneumocytes. Surfactant consists of 90% phospholipids
(primarily phosphatidylcholine and phosphatidylglycerol) and 10% proteins (surfactant proteins [SP]-A,
SP-B, SP-C). Surfactant is packaged into lamellar bodies and is excreted into the alveolar space where it
unravels and forms a monolayer on alveolar surfaces. Lamellar bodies can also pass into the amniotic
cavity and, hence, are found in amniotic fluid. The surfactant functions to reduce the surface tension in
the alveoli, preventing atelectasis. When surfactant is deficient, the small alveoli collapse and the large
alveoli become overinflated and stiff, which has been associated with increased risk of developing
respiratory distress. The status of fetal lung maturity is reflected in the concentration of surfactant in the
form of phospholipids (see FLP/8929 Fetal Lung Profile, Amniotic Fluid) and lamellar bodies present in
amniotic fluid. Lamellar bodies are similar in size to platelets and can be quantified on a hematology
analyzer utilizing the platelet channel and used to estimate fetal lung maturity.
Useful For: Predicting fetal lung maturity and assessing the risk of developing neonatal respiratory
distress syndrome, when performed during 32 to 39 weeks gestation Useful in cases in which lamellar
body count results are indeterminate
Interpretation: Lamellar body count (LBC): Amniotic fluid LBC >50,000/mcL is predictive of fetal
lung maturity. Amniotic fluid LBC or = 2.5 and PG absent: indeterminate LS ratio < 2.5 and PG trace: indeterminate L/S ratio > or
= 2.5 and PG trace: mature PG present: mature
Reference Values:
Immature: 50,000/mcL
Cutoffs are based on consensus protocol (Neerhof M, Dohnal JC, Ashwood ER, et al: Lamellar body
counts: a consensus on protocol. Obstet Gynecol 2001;97:318-320)
Clinical References: 1. Fetal Lung Maturity. ACOG Practice bulletin. Obstet Gynecol September
2008;112(3):717-726 2. Eby C, Lu J, Gronowski AM: Lamellar Body Counts Performed on Automated
Hematology Analyzers to Assess Fetal Lung Maturity. Lab Med 2008;39(7):15 3. Haymond S, Luzzi V,
Parvin C, Gronowski A: A Direct Comparison Between Lamellar Body Counts and Fluorescent
Polarization Methods for Predicting Respiratory Distress Syndrome. Am J Clin Pathol
2006;126:894-899 4. Szallasi A, Gronowski A, Eby C: Lamellar Body Count in Amniotic Fluid: A
Comparative Study of Four Different Hematology Analyzers. Clin Chem 2003;49(6):994-997 5.
Grenache DG, Gronowski AM: Fetal lung maturity. Clin Biochem 2006;39:1-10 6. Neerhof M, Dohnal
JC, Ashwood ER, et al: Lamellar body counts: a consensus on protocol. Obstet Gynecol
2001;97:318-320
Lamellar Body Count, Amniotic Fluid
Clinical Information: Fetal lung maturity testing is used to determine the risk for developing
respiratory distress syndrome (RDS) in infants born prematurely (32-39 weeks). The risk for developing
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