摘要:
A method for the determination of hemoglobin and hematocrit by means of an apparatus that is capable of controlling the temperature of a defined subcutaneous volume of human skin. The method involves a calculation of hemoglobin concentration and hematocrit value that takes into consideration the values of optical parameters of the sample at various pre-set temperatures. The apparatus and method employ steady state optical measurements of samples, such as, for example, human tissue, by means of a reflectance tissue photometer and localized control of the temperature of the sample. According to the method of this invention, an optical signal from a defined subcutaneous volume of human skin is measured as the temperature of this volume is controlled. The method and apparatus of this invention allow determination of hemoglobin concentration and hematocrit value non-invasively in a population of subjects having different skin colors by means of steady state reflectance measurements. The method of this invention for determination of hemoglobin concentration and hematocrit value is useful for monitoring patients, testing at the point of care, and screening for anemia. In contrast to other attempts in the prior art that rely on signals of cardiac pulses, the method of this invention has the advantage for the determination of analytes in weak cardiac pulse situations, such as, for example, in elderly patients.
摘要:
A method for determining the concentration of an analyte in a biological sample comprising the steps of: (1) providing an optical measuring instrument comprising a thermally controllable optical measuring element that comes into contact with the surface of the biological sample; (2) applying a coupling agent to the optical measuring element or to the surface of the biological sample or to both so that the coupling agent will be disposed at the interface of the surface of the biological sample and the optical measuring element; (3) measuring optical properties of the biological sample by means of the optical measuring instrument; and (4) correlating the optical properties of the biological sample with the concentration of the analyte in the biological sample. The coupling agent can be selected from the group consisting of silicone oil, mineral oil, polyethylene glycols, and oils from natural resources.
摘要:
A method for determining the concentration of an analyte in a biological sample comprising the steps of: (1) providing an optical measuring instrument that comprises at least one thermally controllable optical measuring element that comes into contact with the surface of the biological sample; (2) applying an inert, thermally conductive, optically transparent coupling agent to the at least one optical measuring element or to the surface of the biological sample or both so that the coupling agent will be disposed at the interface of the surface of the biological sample and the at least one optical measuring element; (3) measuring optical properties of the biological sample by means of the optical measuring instrument; and (4) correlating the optical properties of the biological sample with the concentration of the analyte in the biological sample. A coupling agent suitable for this invention must have several properties to enable it to help decrease measurement variation, especially drift. One of the most important properties is sufficiently high optical stability that the optical properties of the coupling agent do not change even during prolonged experiments, such as oral glucose tolerance tests. Secondly, the coupling agent should have sufficiently high thermal conductivity to allow fast, efficient heat transfer between the optical probe and the biological sample. Third, the coupling agent should have sufficiently high viscosity to prevent it from migrating from the measurement area. Yet, it should also have sufficiently low viscosity to allow sufficient contact between the optical probe and the biological sample and to permeate into any small pockets between the probe and the biological sample that would otherwise be filled with the air. Fourth, the coupling agent should be inert. Material from the coupling agent should not diffuse into the biological sample and material from the biological sample should not diffuse into the coupling agent.
摘要:
Devices and methods for non-invasively measuring at least one parameter of a sample, such as the presence of a disease condition, progression of a disease state, presence of an analyte, or concentration of an analyte, in a biological sample, such as, for example, a body part. In these devices and methods, temperature is controlled and is varied between preset boundaries. The methods and devices measure light that is reflected, scattered, absorbed, or emitted by the sample from an average sampling depth, dav, that is confined within a region in the sample wherein temperature is controlled. According to the method of this invention, the sampling depth dav, in human tissue is modified by changing the temperature of the tissue. The sampling depth increases as the temperature is lowered below the body core temperature and decreases when the temperature is raised within or above the body core temperature. Changing the temperature at the measurement site changes the light penetration depth in tissue and hence dav. Change in light penetration in tissue as a function of temperature can be used to estimate the presence of a disease condition, progression of a disease state, presence of an analyte, or concentration of an analyte in a biological sample. According to the method of this invention, an optical measurement is performed on a biological sample at a first temperature. Then, when the optical measurement is repeated at a second temperature, light will penetrate into the biological sample to a depth that is different from the depth to which light penetrates at the first temperature by from about 5% to about 20%.
摘要翻译:用于非侵入性地测量样品的至少一个参数的装置和方法,例如疾病状况的存在,疾病状态的进展,分析物的存在或分析物的浓度, 例如,身体部位。 在这些装置和方法中,控制温度并在预设的边界之间变化。 方法和装置测量由样品中的平均采样深度d> av is is is is is is is measure measure measure measure measure measure measure measure measure measure measure measure measure measure measure or or wherein wherein wherein wherein wherein wherein。。。。。。。。 根据本发明的方法,通过改变组织的温度来改变人体组织中的采样深度d>。。 当温度降低到体芯温度以下时,采样深度增加,当温度升高到体芯内温度以上时,采样深度降低。 改变测量部位的温度会改变组织中的光穿透深度,从而改变组织的光穿透深度。 可以使用作为温度的函数的组织中的光穿透的变化来估计生物样品中疾病状况,疾病状态的进展,分析物的存在或分析物的浓度的存在。 根据本发明的方法,在第一温度下对生物样品进行光学测量。 然后,当在第二温度下重复光学测量时,光将穿透生物样品至与第一温度下的光渗透约5%至约20%的深度不同的深度。
摘要:
A method and apparatus for the measurement of trans-cutaneous diffuse reflectance at a single sampling distance for determining the concentration of an analyte in a biological sample, such as, for example, human tissue. The determination of the concentration of the analyte has been found to depend on the sampling distance and reaches an optimal result at a defined sampling distance for a given analyte and a given sample. The method involves measuring the light re-emitted from the sample at a distance from a light introduction site and correlating the intensity of the re-emitted light to the concentration of an analyte. For a given sample, the distance between the light collection site and a light introduction site (i.e., the sampling distance) corresponds to the depth from the surface into the sample at which scattering and absorption events significantly affect the intensity of re-emitted light (i.e., the sampling depth). Prior knowledge about the sample determines the optimal sampling depth for performing a measurement for a specific analyte and the corresponding sampling distance needed to reach that optimal sampling depth. Optimization of the sampling distance, as well as the correlation relationship, can be established in a calibration procedure.
摘要:
A method and apparatus for measuring the concentration of an analyte of interest, e.g. glucose, in blood non-invasively, i.e., without penetrating the skin or obtaining a biological sample from the body of a patient. The method and apparatus uses a plurality of measurement channels with appropriate wavelengths of interest to control variations of signal and to separate the contribution of the analyte of interest from those of interfering compounds. The method and apparatus of this invention can also be adapted to allow a portion of a body part to be engorged with blood to bring about greater accuracy in optical measurements. In the method of this invention, at least two similar, but not identical, measurements are made concurrently. For example, at least two measurements can be made with similar, but not identical, wavelengths of electromagnetic radiation. The two wavelengths should not be overlapping to allow maximum non-identity. By making measurements concurrently, each measurement channel in the system experiences variations as they occur substantially simultaneously in all channels. By selecting one of the channels as a reference channel and by normalizing the optical measurements of the other channels to this reference channel, the variations common to all channels are eliminated. Removing these common variations from the optical measurements by normalization, such as by calculating ratios of the measurement of each of the measuring channels to that of the reference channel, will allow the actual changes of the signal for a specific analyte of interest to be measured.
摘要:
Devices and methods for non-invasively measuring at least one parameter of a sample, such as the presence or concentration of an analyte, in a body part wherein the temperature is controlled. The present invention measures light that is reflected, scattered, absorbed, or emitted by the sample from an average sampling depth, dav, that is confined within a temperature controlled region in the tissue. This average sampling depth is preferably less than 2 mm, and more preferably less than 1 mm. Confining the sampling depth into the tissue is achieved by appropriate selection of the separation between the source and the detector and the illumination wavelengths. In another aspect, the invention involves a method and apparatus for non-invasively measuring at least one parameter of a body part with temperature stepping. In another aspect, the invention involves a method and apparatus for non-invasively measuring at least one parameter of a body part with temperature modulation. In another aspect, the invention provides an improved method of measuring at least one parameter of a tissue sample comprising the steps of: (a) lowering the temperature of said tissue sample to a temperature that is lower than the normal physiological temperature of the body; and (b) determining at least one optical property of said tissue sample.
摘要:
Apparatus and method for non-invasively measuring at least one optical parameter of a sample, particularly a sample of tissue that comprises a plurality of layers. The at least one parameter can be used to determine the presence or concentration of an analyte of interest in the sample of tissue. The apparatus and method of the present invention (1) measure light that is substantially reflected, scattered, absorbed, or emitted from a shallower layer of the sample of tissue, (2) measure light that is substantially reflected, scattered, absorbed, or emitted from a deeper layer of the sample of tissue, (3) determine at least one optical parameter for each of these layers, and (4) account for the effect of the shallower layer on the at least one optical parameter of the deeper layer. Specifying the sampling depth allows determinations of the optical properties of a specific layer of the sample of the tissue, e.g., dermis, and decreases interference from other layers, e.g., stratum corneum and epidermis, in these determinations.
摘要:
Apparatus and method for non-invasively measuring at least one optical parameter of a sample, particularly a sample of tissue that comprises a plurality of layers. The at least one parameter can be used to determine the presence or concentration of an analyte of interest in the sample of tissue. The apparatus and method of the present invention (1) measure light that is substantially reflected, scattered, absorbed, or emitted from a shallower layer of the sample of tissue, (2) measure light that is substantially reflected, scattered, absorbed, or emitted from a deeper layer of the sample of tissue, (3) determine at least one optical parameter for each of these layers, and (4) account for the effect of the shallower layer on the at least one optical parameter of the deeper layer. Specifying the sampling depth allows determinations of the optical properties of a specific layer of the sample of the tissue, e.g., dermis, and decreases interference from other layers, e. g., stratum corneum and epidermis, in these determinations.
摘要:
A method for collecting optical data at two morphologically similar, substantially non-overlapping, and preferably adjacent, areas on the surface of a tissue, while the temperature in each area is being maintained or modulated according to a temperature program. The optical data obtained are inserted into a mathematical relationship, e.g., an algorithm, that can be used to predict a disease state (such as the diabetes mellitus disease state) or the concentration of an analyte for indicating a physical condition (such as blood glucose level). This invention can be used to differentiate between disease status, such as, for example, diabetic and non-diabetic. The method involves the generation of a calibration (or training) set that utilizes the relationship between optical signals emanating from the skin under different thermal stimuli and disease status, e.g., diabetic status, established clinically. This calibration set can be used to predict the disease state of other subjects. Structural changes, as well as circulatory changes, due to a disease state are determined at two morphologically similar, but substantially non-overlapping areas on the surface of human tissue, e.g., the skin of a forearm, with each area being subjected to different temperature modulation programs. In addition to determination of a disease state, this invention can also be used to determine the concentration of an analyte in the tissues. This invention also provides an apparatus for the determination of a disease state, such as diabetes, or concentration of an analyte, such as blood glucose level, by the method of this invention.