Point-of Care System for Determination of Bilirubin Capacity in Neonates

描述（由申请人提供）：人血清白蛋白能够以高亲和力结合胆红素，从而将其隔离并减轻其对黄疸新生儿的有害神经影响。尽管大量研究表明，血液中胆红素水平相对于白蛋白结合位点的水平是评估胆红素相关脑损伤风险的关键因素，但新生儿黄疸的管理仍然基于替代因素，如胎龄和出生体重沿着胆红素水平。现在存在许多测定胆红素水平的方法。测定血清总胆红素的常用方法是湿化学法。多年来已经开发了测定血清中储备白蛋白结合能力和未结合（动员）胆红素水平的方法，但由于它们仍然是繁琐的实验室检查，因此没有一种方法获得常规使用。提议的工作是开发一种利用胆红素天然荧光的即时护理系统（小型荧光计和一次性用品）。胆红素与白蛋白结合产生荧光信号，可在原始血液中检测到。通过荧光测定，该白蛋白结合胆红素水平等同于通过标准方法测定的总血清胆红素，因为未结合胆红素水平总是小得多，直到白蛋白结合接近饱和。胆红素的储备结合能力可以通过向血液中加入过量的胆红素来测量，荧光的增加是由于新结合的胆红素。这种方法测量实际结合能力，并自然考虑到白蛋白水平、其他溶质的竞争结合和减弱的结合位点等因素。 导致这种荧光方法的基础研究在三十多年前就有报道，实验室仪器的原型在临床环境中设计和测试。当时，新的管理指南在缺乏约束性数据的情况下，加上光疗的广泛使用，避免了它们的使用。由于目前的做法，非常早期释放显然健康的新生儿和黄疸的持续发展在家里，管理已变得复杂。与“现场”儿科医生的访谈表明，一种廉价且易于使用的即时护理系统，仅需要“脚跟贴”量的血液，基本上不需要对标本进行操作，将从单独提供统计胆红素水平的能力提供更好的管理，并且结合数据将额外提供管理指导，这可能更有效且成本更低。在床边使用也应该有利于黄疸住院低体重儿和患病新生儿的管理。 虽然用现代光电技术显然是可行的，但是对于这样的小型护理点系统的开发存在若干设计和实际挑战。拟议的工作将面对和克服这些挑战。 公共卫生相关性：核黄疸是一种可预防的新生儿脑损伤，在美国再次出现（1-5）。目前测定胆红素的方法没有考虑到儿童安全隔离胆红素的能力，必须根据胎龄，年龄，体重和其他因素进行解释（6）。所提出的血液荧光计直接测量胆红素结合和储备胆红素结合能力，并且具有更快、更便宜并且在护理点可用的潜力。

DESCRIPTION (provided by applicant): Human serum albumin is capable of binding bilirubin with high affinity, thus sequestering it and mitigat- ing its harmful neurological effects in jaundiced newborns. Despite considerable work indicating that the level of bilirubin in the blood relative to the level of albumin binding sites is a key factor in assessing risk for bilirubin associated brain damage, management of neonatal jaundice remains based upon proxies, such as gestational age and birth weight along with the bilirubin level. A number of methods for assaying the bilirubin level now ex- ist. The common approaches determine the total serum bilirubin by wet chemical methods. Methods to assay reserve albumin binding capacity and unbound (mobilized) bilirubin levels in serum have been developed over the years but none have achieved routine use because they remain cumbersome laboratory tests. The pro- posed work is to develop a point-of-care system (a small fluorometer and disposables) that makes use of bili- rubin's natural fluorescence. Bilirubin bound to albumin produces a fluorescence signal that can be detected in raw blood. Assayed by fluorescence this albumin-bound bilirubin level equates to the total serum bilirubin by standard methods since the unbound bilirubin level is always much smaller until albumin binding approaches saturation. The reserve binding capacity for bilirubin can be measured by adding excess bilirubin to the blood, with the increase in fluorescence being due to the newly bound bilirubin. This approach measures the actual binding capacity and naturally takes into account factors such as albumin levels, competing binding by other solutes and weakened binding sites. The basic studies leading to this fluorometric approach were reported more than thirty years ago and prototype laboratory-bound instruments were devised and tested in clinical settings. At that time new manage- ment guidelines in the absence of binding data coupled with wide use of phototherapy obviated their use. With the current practice of very early release of apparently healthy newborns and susbsequent development of jaundice at home, management has become complicated. Interviews with pediatricians "on the ground" have indicated that an inexpensive and easy to use point-of-care system that requires only a "heel stick" quantity of blood and essentially no manipulation of the specimen, would provide for better management from the ability to provide a stat bilirubin level alone, and binding data would additionally provide guidance in management that may be more efficient and less costly. Use at crib-side should also benefit the management of the jaundiced hospitalized low-birth-weight and sick neonate. While apparently feasible with modern optoelectronic technology, several design and practical chal- lenges exist for the development of such a small point-of-care system. The proposed work will confront and overcome these challenges. PUBLIC HEALTH RELEVANCE: Kernicterus is a preventable brain injury in neonates, and it is reemerging in the USA (1-5). Present-day methods of assaying bilirubin do not take into account a child's ability to safely sequester bilirubin and must be interpreted in terms of gestational age, age, weight and other factors (6). The proposed hematofluorometer directly measures bilirubin binding and reserve bilirubin binding capacity, and has the potentials to be faster, less expensive and available at the point of care.