EP1012572A1

EP1012572A1 - Hemoglobin measurement device

Info

Publication number: EP1012572A1
Application number: EP97948369A
Authority: EP
Inventors: Charles R. Preston; Peter A. Bourdelle; Laverne Waber
Original assignee: Adaltis Inc
Current assignee: Adaltis Inc
Priority date: 1996-11-20
Filing date: 1997-11-20
Publication date: 2000-06-28
Also published as: WO1998022777A1; AU5445498A; JP2000504984A; EP1012572A4; CA2272624A1

Abstract

The invention relates to a diagnostic medical device and in particular to a hemoglobin measurement device for measuring hemoglobin content in a blood sample. A hemoglobin sample is prepared from a blood sample by mixing a portion of the blood sample with a diluent and lyse appropriate to release hemoglobin from red blood cells in the blood sample. The sample is then provided to a hemoglobin measurement device (10) where a hemoglobin measurement is made. The device has a chamber (110) with a light source (116) and light detector (118) located at opposite ends and operable at wavelengths that are absorbed or reflected by the hemoglobin. The chamber also includes hemoglobin sample inlet (112) and outlet (114) ports which extend through the body into the measurement chamber.

Description

HEMOGLOBIN MEASUREMENT DEVICE

Field of the Invention

The invention relates to a diagnostic medical device, and in particular to a blood cell analyzer having a hemoglobin measurement device.

Background of the Invention

The hemoglobin level in blood is an important aid to a medical practitioner in the diagnosis of many abnormal conditions in the body such as anemia. The hemoglobin content in blood is known to be between 12 and 16 grams (g) per 100 milliliters (ml) of blood in females and between 14 and 18 g per 100 (ml) in males. Hemoglobin levels above or below these levels may indicate an abnormal condition and should be brought to the attention of a medical practitioner.

Several methods and devices have been developed to measure hemoglobin. It is known that hemoglobin can be detected and measured by chemical analysis or the analysis of color absorbance of an unknown sample with a known sample. However, the methods and devices using color absorbance techniques are known to require expensive, bulky, and cumbersome equipment that require continuous inspection and maintenance. In addition, none of the methods or devices known in the prior art are capable of sampling and measuring hemoglobin with small low power light sources as the hemoglobin is passing through or paused in the measuring device.

The present invention addresses and solves the problems of conventional hemoglobin measurement equipment by providing an inexpensive, compact, and efficient disposable device that requires little or no inspection and maintenance.

Summary of the Invention

The present invention relates to a diagnostic medical device, and in particular to a hemoglobin measurement device for analyzing the hemoglobin content of blood samples. A hemoglobin sample is prepared from a blood sample and provided to the hemoglobin measurement device, for example, by a conventional blood analyzer. The hemoglobin sample is prepared by mixing a portion of the blood sample with diluent and lyse in a portion necessary to release hemoglobin from red blood cells in the blood sample. The hemoglobin sample is pumped following an appropriate interval of time through the hemoglobin measurement device where a hemoglobin measurement is made.

The device has a chamber with a light source and light detector located at opposite ends of the chamber and operable at an optical wavelength that is absorbed and/or reflected by the hemoglobin. The hemoglobin level is determined as a function of the light intensity emitted at a preselected wavelength and transmitted through the sample and the light intensity detected. This measurement can be made when the hemoglobin sample is flowing through or stationary in the chamber. In one aspect of the invention, a hemoglobin measurement device includes a body having a measurement chamber, a hemoglobin sample input port, and a hemoglobin sample output port. Both ports extend through the body into the measurement chamber to provide a flow of hemoglobin sample through the chamber. The invention includes a light source that is directed into the chamber which emits light at a preselected wavelength through a flowing or stationary hemoglobin sample.

The invention further includes a light detector that is directed at the light source and positioned such that the light passing through the hemoglobin sample is directed onto and detected by the detector. The hemoglobin level in the blood sample is determined from the amount of light on the detector as a loss of light intensity from absorption by the hemoglobin.

Brief Description of the Drawings

For a better understanding of the present invention, reference is made to the accompanying drawings. The drawings show embodiments of the invention as presently preferred. However, it should be understood that the invention is not limited to the precise arrangements and instrumentality shown in the drawings.

Figure 1 is a cross-section view of a hemoglobin measurement device according to a preferred embodiment of the present invention.

Figure 2 is a cross-sectional view of a hemoglobin measurement device having an insert and light source according to another preferred embodiment of the present invention.

Figure 3 is a sectional view of the insert and light source of the hemoglobin measurement device shown in Figure 2.

Detailed Description of the Invention

Referring to the drawings, where like elements are identified by like numerals, there is shown in Figure 1 a hemoglobin measurement device 10 according to a preferred embodiment of the present invention. Referring to Figure 1, the hemoglobin measurement device 10 includes a body 130 with a chamber 110. The body 130 has a cap portion 132 for retaining a light source 116, a light detector 118, and a pair of collar portions 134 for protecting an retaining the electrical connections 120, 190 to the detector 118 and source 116, respectively. The body 130 and chamber 110 may have open or closed ends 136. The chamber can be made into any shape including, but not limited to, cylindrical, spherical, or frustoconical. During operation of the device 10, the chamber 110 has a flow of blood sample supplied to the chamber by an external blood sample source such as, but not limited to, conventional blood analyzer equipment equipped with fluid pumping and withdrawing means.

In a preferred embodiment, a flow of hemoglobin sample is produced in the chamber by a supply of hemoglobin sample coupled to an input port 112 that extends through the body 130. The hemoglobin sample enters the chamber 130 through the input port 112, flows through the chamber where it is removed by exiting a sample output port 114 that is coupled to a blood sample removing means (not shown). In summary, blood samples enter the measurement chamber 110 through the input port 114, pass through the chamber 110 and across a light path formed by the light source 116 and detector 118 which measure the hemoglobin level in the blood sample, and the samples exit out of the chamber 110 through the output port 114. It is to be understood that the direction of flow of the hemoglobin sample through the chamber 110 can be in either direction and through either port 112, 114. The direction of flow and nomenclature of the ports 112, 114 were merely selected here for convenience.

In one aspect of the present invention, the input port 112 and output port 114 are tubes that exit the body 130 at a preferred angle θ that is about 60 degrees with respect to the chamber's surface 131. It is under stood that the angle 0 of the input port 112 and output port 114 need not be the same and can be an angle in the range of 10 to 90 degrees.

In another aspect of the invention, particularly when the angle of the ports 112,114 is 60 degrees with respect to the interior surface 131 of the chamber 110, the blood sample creates a vortex as it enters the chamber 130. The vortex produces a desirable effect by reducing the accumulation of air bubbles and debris on the surface of the light detector 118 and light source 116 which improves hemoglobin measurement accuracy and reliability.

In another aspect of the invention, the interior surface 131 of the chamber 110 is made to produce a hydrophillic condition. One way this can be achieved is by texturing the chamber surface 131 by making it rough or irregular. For example, the body 130 can be made from a material such as metal or plastic that is molded, milled or drilled to produce the chamber 110 having a surface 131. The chamber surface 131 is typically treated to produce a hydrophillic condition. However, it is recognized that an extremely high hydrophillic surface can be produced without the need of additional surface treatment. When a hydrophillic surface treatment is required, it can be accomplished by mechanical or chemical abrasions such as sand blasting or a chemical enchant to produce an irregular surface. The irregular surface improves the wetting of the chamber surface 131 by reducing bubble formation on the surface 131 as the sample fills the chamber 130. Thus, bubble content in the chamber 130 is reduced which greatly improves hemoglobin measurement accuracy.

At one end of the body 130 is a light source 1 16 that is directed into the chamber 110. The light source emits light into the chamber 110 at a preselected wavelength typically in the range of 520 to 580 nm. Unlike prior art systems, the present invention employs an unfiltered light source that directly produces emitted light at the proper wavelength. In another aspect of the invention, the light source has a peak wavelength of 557 nm and a dominant wavelength at about 560 nm. However, it is understood that blood hemoglobin will absorb light in a bandwidth of wavelengths about 549 nm which is also contemplated by the present invention.

Opposite the light source 116 is a light detector 118. The light detector 118 is directed at the light source 116 and positioned such that the light passes through the flowing blood sample onto the detector 118 where it is detected. A hemoglobin level is then determined as a loss of light intensity due to absorption by the hemoglobin. Therefore, the difference in intensity of light emitted by the light source 116 and the light received by the detector 118 is related to the amount of hemoglobin present in the blood sample. This phenomenon is also referred to here as the loss or attenuation of light by the hemoglobin. In a preferred embodiment of the present invention, pre-mixed fluid, also referred to as hemoglobin sample, contains blood, diluent, and a Lysing agent, that is pumped or drawn by a pump (not shown) into the chamber 110. As described above, the hemoglobin sample may enter the body 130 through an input port 112 and exits through an output port 114. The source of the hemoglobin sample can be obtained from a blood sample supply or any conventional sampling device having a pump or drawing capability.

The hemoglobin sample is pumped or drawn through the chamber 110 or made stationary in the chamber and illuminated by a light source 116. In another aspect of the invention, the light source or the detector 118 or both can be separated from the hemoglobin sample by an optically permeable barrier 122 such as a transparent window composed of glass or plastic. The light source 116 is of a frequency that is either reflected or absorbed, or both, by hemoglobin. The light from the light source 116 propagates through the hemoglobin sample where it is attenuated by absorption or reflection, or both, according to the amount of hemoglobin present in the fluid. In another aspect of the invention the preferred light source is a green light LED such as, but not limited to, an LPK382 green LED manufactured by Siemens, Inc. In another aspect of the invention the light detector 118 is a silicon photodiode.

Light from the source 116 that is not reflected or absorbed by the fluid is received by the light detector 118 and converted into an electric signal. The signal is carried on a cable 120 and represents the hemoglobin level of the fluid passing through the chamber 110. The measurement of the hemoglobin in the fluid is made either as the fluid moves through or is paused in the chamber 110.

In another aspect of the invention, the fluid is drawn through the chamber 110 by a negative pressure applied to the output port 114. The output port 114 is located proximate to the light detector 118 thereby preventing the accumulation of air bubbles and debris on the surface of light detector 118. As the hemoglobin sample is drawn into the chamber 110 a vortex effect is created by the hemoglobin sample flow and the angle of the input port 112 and output port 114. The ports are openings into the chamber 110 which can be, but are not limited to, tubes that are attached to the body 130 and chamber 110. Referring to Figure 2, in another aspect of the invention the hemoglobin measurement device includes a body 130 having at least one thermal equilibrium vent 172 . The thermal equilibrium vent 130 is passageway made through the body 130 allowing heat produced by the light source 116 to dissipate outside the body 130. Typically, air surrounding the source 116 will carry the heat produced by the source 116 by convection through the vent 130.

Referring to Figures 2 and 3, in another aspect of the invention the light source 116 and the light detector 118 are each mounted to an insert 140 that is attached to the body 130 by an insert locking device 160. The insert 140 can be made to accept either a light source 116 or a light detector 118. In one aspect of the invention, the light detector 116 is mounted to its insert 140 by a bead of epoxy 170 after it is adjusted and retained in place by a retaining device 150.

Referring to Figure 3, the light source 116 can be mounted directly or by means of a molded or cast assembly 180. In addition, the detector 118 can also mounted directly or by means of a molded or cast assembly (not shown). The light source 1 16 is adjusted by changing its location within the insert 140. The adjustment is made to produce a desired amount of columnated light when the light source 116 emits light. To improve columnation of light a columnating device 141 is provided which can be located in the insert 140. The columnating device 141 has a spherical reflecting surface 142 that is located about the light source 116. The light source 116 is directed through the columnating device 141 and the emitted light is reflected by the reflecting surface 142 which forms the emitted light into a column. In yet another aspect of the invention, the hemoglobin measurement device 10 has a modular design for the body 130, modular light source 20, and modular light detector 30. The modular design allows the light source 20 and detector 30 to have the same form and fit in the body 130. The body 130, as explained above, provides uniform sample flow through the chamber 110 when it is suppled with hemoglobin samples through either port 112, 114. The modular light source 20 includes a light source 160 mounted in an insert 140. The modular light detector 30 includes a light detector 118 mounted in an insert 140. The insert 140 can be mounted to the body 130 by commonly sized openings 200 and retained by a common locking device 160. Accordingly, the insert with the light source and the insert with the light detector can be interchangeably attached to the body 130 and retained by an insert locking device. Therefore, the source 20 and detector 30 can be mounted in the body 130 without regard to the direction of flow. This feature reduces the number and difference in parts and greatly improves reliability and serviceability.

The present invention may be embodied in other variant forms where the variation does not substantially differentiate from the essential novelty and uniqueness revealed in the foregoing disclosure. Reference should therefore be made to the appendant claims rather than the foregoing specification, as indicating the scope of the invention. It should be understood that many modifications, variations and changes may be made without departing from the spirit and scope of the invention as defined in the claims.

Claims

CLAIMSWhat is claimed is:

1. A hemoglobin measurement device, comprising: a body having a measurement chamber, a sample input port and a sample output port, both ports extending through the body into the chamber for providing a flow of hemoglobin sample through the chamber; a light source directed into the chamber and emitting light at a preselected wavelength through the hemoglobin sample; and a light detector directed at the light source and positioned such that the light passes through the hemoglobin sample onto the detector and detected; wherein a hemoglobin level is determined from the detected light as a loss of light intensity from absorption by the hemoglobin.

2. The hemoglobin measurement device according to claim 1 , wherein the hemoglobin level is determined as the hemoglobin sample flows through the measurement chamber.

3. The hemoglobin measurement device according to claim 1 , wherein the location of the light emitted by the light source formed into a column.

4. The hemoglobin measurement device according to claim 1, wherein the light source has a wavelength between 520 and 580 nm.

5. The hemoglobin measurement device according to claim 4, wherein the light source is unfiltered.

6. The hemoglobin measurement device according to claim 1, wherein the light source has a peak wavelength at 557 nm and a dominant wavelength at about 560 nm.

7. The hemoglobin measurement device according to claim 1, wherein the chamber has a shape that is cylindrical, spherical, or frustoconical.

8. The hemoglobin measurement device according to claim 7, wherein the sample input port and the output port are located at opposite ends of the chamber.

9. The hemoglobin measurement device according to claim 1 , wherein the sample input port enters the chamber at an angle to the chamber walls sufficient to create a vortex at the detector or emitter.

10. The hemoglobin measurement device according to claim 9, wherein the angle to the chamber wall is about 60° with respect to the chamber's walls.

11. The hemoglobin measurement device according to claim 1, wherein the body has a first opening into the chamber that is sealed by the light detector.

12. The hemoglobin measurement device according to claim

1 , wherein the body has a second opening into the chamber that is sealed by the light source.

13. The hemoglobin measurement device according to claim 1, wherein the body has at least one opening that is sealed by an optically permeable barrier.

14. The hemoglobin measurement device according to claim 13, wherein the optically permeable barrier is glass or plastic.

15. The hemoglobin measurement device according to claim 1 , wherein the chamber has a textured surface.

16. The hemoglobin measurement device according to claim

15, wherein the textured surface is made by sandblasting.

17. A hemoglobin measurement device, comprising: a body having a measurement chamber, a sample input port, a sample output port, and at least one thermal equilibrium vent, where the input and output ports extending through the body into the chamber for providing a sample flowing through the chamber; a light source directed into the chamber and emitting light at a preselected wavelength through the measurement chamber; and a light detector directed at the light source and positioned such that the light passes through the sample onto the detector where it is detected, wherein the equilibrium vent allows heat to dissipate from the light source and a hemoglobin level is determined from the detected light as a loss of light intensity from absorption by the hemoglobin.

18. The hemoglobin measurement device according to claim

17, wherein the light source is mounted to an insert that is attached to the body by an insert locking device.

19. The hemoglobin measurement device according to claim

18, wherein the light detector is mounted to an insert that is attached to the body by an insert locking device.

20. The hemoglobin measurement device according to claim

19, wherein the insert with the light source and the insert with the light detector can be interchangeably attached to the body and retained by an insert locking device.

21. The hemoglobin measurement device according to claim 17, wherein the light source is directed through a columnating device forming the light into a column as it is emitted into the measurement chamber.

22. The hemoglobin measurement device according to claim

21, wherein the columnating device is a spherical reflecting surface about the light source.

23. The hemoglobin measurement device according to claim

17, wherein the equilibrium vents are located about the light source.

24. The hemoglobin measurement device according to claim

17, wherein the chamber has a textured surface.

25. A hemoglobin measurement device, comprising: a measurement chamber having an irregular surface and providing a flow of sample through the chamber, and a light source directing light into the chamber and onto a light detector, wherein the light source emits light at a preselected wavelength through the sample as it flows through the measurement chamber and a hemoglobin level is determined from a loss of light intensity absorbed by the hemoglobin.

26. The hemoglobin measurement device according to claim 25, wherein the chamber has a flow of sample provided by a sample input port connected to a blood sample supply and a sample output port connected to a blood sample removal system, both ports extending into the chamber for providing a sample flow in and out of the chamber.

27. The hemoglobin measurement device according to claim 25, wherein the surface is made irregular by sandblasting.