RESUMO
Accurate assessment of fetal lung maturity is essential in the management of high-risk obstetric patients. New rapid techniques have been developed to supplement time-consuming chromatographic methods. We compared one of these newer methods, the TDx-FLM, to the standard tests for fetal pulmonary maturity. There was an excellent correlation between the TDx and the lecithin-sphingomyelin ratio (r = 0.78). Although a TDx value of 70 or greater is considered mature, we found a value of 50 or greater predictive of fetal lung maturity in 100% of cases, and have chosen to redefine a mature value as 50 or greater in our institution. This value has greatly enhanced the clinical applicability of the test, allowing use of a large number of specimens from the previously poorly understood and often disregarded borderline category.
Assuntos
Líquido Amniótico/química , Maturidade dos Órgãos Fetais , Pulmão/embriologia , Idade Gestacional , Humanos , Fosfatidilcolinas/análise , Fosfatidilgliceróis/análise , Esfingomielinas/análiseRESUMO
The rapid, accurate determination of serum human chorionic gonadotropin (beta-hCG) levels in the 900- to 2000-IU/L range is a critical element in the treatment of patients with suspected ectopic pregnancy. Using the Abbott IMx system (Abbott Laboratories, North Chicago, Ill), beta-hCG levels can be determined on an undiluted sample up to 1000 IU/L. A sample with beta-hCG level greater than 1000 IU/L is automatically diluted and the diluted sample redetermined. Unfortunately, employing a 1:200 fixed dilution can produce a working sample that contains an beta-hCG concentration that does not fall on a linear portion of the standard curve (<7.5 IU/L). This results in a calculated beta-hCG concentration (200 x observed value) that has high error (coefficient of variation up to 21.8%). Additionally, interfering substances in the reagents, which vary in quantity from lot to lot of reagents, further confound accurate beta-hCG determination by the system. Consequently, the Abbott IMx assay system cannot be used as recommended by the manufacturer for routine measurement of serum beta-hCG in the 900- to 2000-IU range. An alternate protocol employing at 1:10 dilution would allow a more accurate beta-hCG determination.