Apparatus and method for sedimentation based blood analysis

In a process useful in measuring the settling of erythrocytes including the steps of, settling a test specimen of blood in a settling tube, and sensing the height of a separation boundary between erythrocyte cells and plasma fluid with a sensing means as said separation boundary lowers to generate an output, the improvement of said process comprising:

• said sensing is accomplished by sensing the reflectivity of said specimen to irradiation, and
• sampling sensed reflectivity data in response to a change in the reflectivity.

In a process useful in sensing the settling of erythrocyte cells including the steps of settling erythrocyte cells of a test specimen of blood in a settling tube, and tracking the settling of a separation boundary between said erythrocyte cells and plasma fluid by periodically sensing a characteristic of said specimen indicating settling of said erythrocyte cells proximate said separation boundary, the improvement in said process comprising:

• said sensing being accomplished by sensing reflectivity of said specimen to at least one of visible light irradiation and infrared irradiation at a sensing rate greater than the rate of occurrence of significant changes in said characteristic;
• and
• periodically sampling said sensed characteristic at sampling times determined by the occurrence of a change in said sensed characteristic over a predetermined threshold.

In a process useful in sensing the settling of erythrocyte cells including the steps of settling erythrocyte cells of a test specimen of blood in a settling tube, and tracking the height in said settling tube of a separation boundary between said erythrocyte cells and plasma fluid by periodically sensing a characteristic of said specimen proximate and separation boundary, the improvement in said process comprising:

• periodically sampling reflectivity of said specimen immediately below said separation boundary to provide tracking data at sequential positions down said settling tube having a height difference between said sequential positions of not more than about 0.1 millimeter;
• and
• periodically sampling said sensed reflectivity at a sampling rate of not less than about twice per second.

In a process useful in sensing the settling rate of erythrocyte cells including the steps of settling erythrocyte cells of a test specimen of blood in a settling tube, and sensing the rate of settling of said erythrocyte cells over a time period by using a beam of radiation to follow a separation boundary between said erythrocyte cells and plasma fluid in said test specimen, the improvement in said process comprising:

• said sensing step being accomplished by sensing changes in a characteristic of said test specimen in a tracking zone from a position proximate to and below said separation boundary up to a position at said separation boundary.

In a process useful in sensing the settling of erythrocyte cells including the step of settling erythrocyte cells of a test specimen of blood in a settling tube, the improvement in said process comprising:

• sensing the reflectivity of said test specimen in a fixed sensing zone at a position which initially is significantly below a separation boundary between said erythrocyte cells and plasma fluid until said separation boundary reaches said fixed sensing zone, and thereafter sampling said reflectivity upon sensing of a significant change therein.