Fields Meredith, Towers Craig V, Howard Bobby C, Hennessy Mark D, Wolfe Lynlee, Weitz Beth, Porter Stephanie
Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, University of Tennessee Medical Center , Knoxville, TN , USA.
J Matern Fetal Neonatal Med. 2015 Jan;28(2):146-8. doi: 10.3109/14767058.2014.914490. Epub 2014 May 14.
To determine whether meconium-contaminated amniotic fluid falsely elevates the lamellar body count in fetal lung maturity testing.
Thirty mothers undergoing amniocentesis for fetal lung maturity testing were prospectively consented. A 2 mL portion of the patient's sample was mixed with a 10% meconium solution and the meconium-stained sample was then run in tandem with the patient's sample used in clinical management. Pure meconium samples without amniotic fluid were also run through the cell counter for analysis.
Following meconium contamination, the lamellar body count value increased in 67% of the cases, decreased in 23% and remained the same in 10%. There were 13 test results that had "immature" values in the uncontaminated patient management sample group and nine of these (69%) became elevated to a "mature" level (a false elevation) following the addition of meconium. All of the 10 pure liquid meconium samples devoid of amniotic fluid processed by the cell counter identified and quantified some particle the size of platelets.
The lamellar body count test result is not reliable in meconium-stained amniotic fluid specimens. There is some unknown particle found in meconium that is the size of platelets/lamellar bodies that can falsely elevate the test result. Currently, the only reliable fetal lung maturity test in meconium-stained amniotic fluid is the presence of phosphatidylglycerol.
确定胎粪污染的羊水在胎儿肺成熟度检测中是否会错误地提高板层小体计数。
前瞻性地征得30位接受羊膜穿刺术进行胎儿肺成熟度检测的母亲的同意。将患者样本的2 mL部分与10%胎粪溶液混合，然后将染有胎粪的样本与临床管理中使用的患者样本一起进行检测。不含羊水的纯胎粪样本也通过细胞计数器进行分析。
胎粪污染后，67%的病例板层小体计数值升高，23%降低，10%保持不变。在未受污染的患者管理样本组中有13个检测结果为“不成熟”值，其中9个（69%）在加入胎粪后升高到“成熟”水平（假阳性升高）。细胞计数器处理的所有10个不含羊水的纯胎粪样本均识别并定量了一些血小板大小的颗粒。
在染有胎粪的羊水标本中，板层小体计数检测结果不可靠。胎粪中发现了一些未知颗粒，其大小与血小板/板层小体相同，可错误地提高检测结果。目前，在染有胎粪的羊水中唯一可靠的胎儿肺成熟度检测是磷脂酰甘油的存在。
