Validation of lamellar body counts using three hematology analyzers.
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.
Lockwood
Christina M
CM
Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA.
Crompton
J Chance
JC
Riley
Joan K
JK
Landeros
Keith
K
Dietzen
Dennis J
DJ
Grenache
David G
DG
Gronowski
Ann M
AM
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
D010743:Phospholipids; D011663:Pulmonary Surfactants