Test Catalog

Test Id : LBC

Lamellar Body Count, Amniotic Fluid

Useful For
Suggests clinical disorders or settings where the test may be helpful

Predicting fetal lung maturity and assessing the risk of developing neonatal respiratory distress syndrome, when performed from 32 to 39 weeks gestation

Method Name
A short description of the method used to perform the test

Impedance

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Lamellar Body Count, AF

Aliases
Lists additional common names for a test, as an aid in searching

Fetal Lung Maturity

Specimen Type
Describes the specimen type validated for testing

Amniotic Fld

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Container/Tube: Amniotic fluid container or plastic vial

Specimen Volume: 2 mL

Collection Instructions:

1. Do not centrifuge

2. Amniotic specimens must be free of blood and meconium contamination.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.75 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject
Centrifuged specimen
Presence of blood or meconium
Reject

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Amniotic Fld Refrigerated (preferred) 28 days
Ambient 7 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

Predicting fetal lung maturity and assessing the risk of developing neonatal respiratory distress syndrome, when performed from 32 to 39 weeks gestation

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

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 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.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Immature: <15,000/mcL

Indeterminate: 15,000-50,000/mcL

Mature: >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)

Interpretation
Provides information to assist in interpretation of the test results

Amniotic fluid lamellar body counts (LBC) above 50,000/mcL are predictive of fetal lung maturity.

 

Amniotic fluid LBC below 15,000/mcL are suggestive of fetal lung immaturity and increased risk of neonatal respiratory distress syndrome (RDS).

 

The main value of fetal lung maturity testing is predicting the absence of RDS. An immature test result for fetal lung maturity is less reliable in predicting the presence of RDS.(1)

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Surfactant secretion into the amniotic fluid is minimal prior to 32 weeks gestation.

 

Fetal lung maturity testing is not indicated beyond week 39.

 

Specimens must not be frozen or centrifuged. Freezing and centrifuging the amniotic fluid falsely decreases the lamellar body count.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Fetal Lung Maturity: ACOG Practice bulletin. Obstet Gynecol. 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

7. Kamath-Rayne BD, Jobe AH: Fetal lung development and surfactant. In: Resnik R ed. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 8th ed. Elsevier; 2019:223-234

Method Description
Describes how the test is performed and provides a method-specific reference

The Sysmex Automated Hematology Analyzer XN-9000 measures platelet count by the impedance method to quantify lamellar body counts.(Instruction manual: Automated Hematology Analyzer/Transportation units XN series [XN-9000] Instructions for Use [North American Edition]. Sysmex Corporation; 02/2014)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Sunday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

Same day/1 day

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

2 weeks

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

83664

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
LBC Lamellar Body Count, AF 19114-8
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
LBCC Lamellar Body Count 19114-8
LBCI Interpretation 59462-2

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports