title: Validation of lamellar body counts using three hematology analyzers.
abstract: The lamellar body count (LBC) represents an alternative method to the TDx-FLM II (Abbott Laboratories, Abbott Park, IL), which is planned to be discontinued, for assessing fetal lung maturity. Our objective was to validate the LBC on 3 hematology analyzers (Coulter LH 750 and Coulter Ac.T diff2, Beckman Coulter, Brea, CA; and Sysmex XE-2100, Sysmex, Mundelein, IL) to serve as a template for other laboratories attempting to perform in-house validation. Intra-assay and interassay coefficients of variation ranged from 1.7% to 21.8% and 1.9% to 7.1%, respectively, and all analyzers demonstrated excellent linearity. Whole blood and meconium were shown to interfere with LBCs, and specimens with these contaminants should be tested using phosphatidyl glycerol. With a TDx-FLM II cutoff of 55 mg/g or more and an LBC cutoff of 50,000/microL or more for maturity, concordance between the TDx-FLM II and the LBC on all instruments was poor (<80% in all cases). Concordance between hematology analyzers was excellent (>or=94%). When laboratories are performing in-house validations, they should not correlate LBC with TDx-FLM II results without outcome data. Correlation with another validated LBC method is preferred.
authors: Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA.
authors: Christina M
authors: CM
authors: Lockwood
authors: J Chance
authors: JC
authors: Crompton
authors: Joan K
authors: JK
authors: Riley
authors: Keith
authors: K
authors: Landeros
authors: Dennis J
authors: DJ
authors: Dietzen
authors: David G
authors: DG
authors: Grenache
authors: Ann M
authors: AM
authors: Gronowski
mesh_terms: D000653:Amniotic Fluid / Q000737:chemistry*; D005260:Female; D005325:Fetal Organ Maturity; D006801:Humans; D007231:Infant, Newborn; D008168:Lung / Q000196:embryology*; D010743:Phospholipids / Q000032:analysis*; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods; D011663:Pulmonary Surfactants / Q000032:analysis*; D012127:Respiratory Distress Syndrome, Newborn / Q000175:diagnosis
chemical_list: D010743:Phospholipids; D011663:Pulmonary Surfactants