Apparatus and method for rapid spectrophotometric pre-test screen of specimen for a blood analyzer

Abstract

A method and apparatus for use in respect of samples which are assessed for quality prior to testing in a clinical analyzer. The method and apparatus identify parameters such as gel level and height of fluid above the gel in blood samples, where appropriate, for the purposes of positioning the specimen for determination of interferents. Such interferents include hemoglobin (Hb), total bilirubin and lipids. These interferents are determined by measurement of absorption of different wavelengths of light in serum or plasma, or other speciments, which are then compared with values obtained through calibration using reference measurements for the respective interferents in serum or plasma or other type of specimen. Determination of temperature of the specimen, as well as specimen type, for example whether the specimen is urine or plasma or serum, may also be carried out.

We claim:  
     
         1 . An apparatus for monitoring a specimen before said specimen is presented for clinical analysis, said apparatus comprised of: 
 a) means for holding a specimen container wherein said means and said container have a longitudinal axis;    b) a first radiation source disposed to direct radiation at said specimen and a first radiation detector disposed to allow collection of transmitted or reflected radiation from said specimen;    c) electrical means to couple said first radiation source to an electronic driver;    d) electrical means to couple said first radiation detector to a computing means which analyzes output from said detector for determination of at least one parameter about said specimen;    e) means to position said container in said axis of said holder based on results from said analysis;    f) a second radiation source;    g) means to transmit radiation from said second radiation source to said specimen;    h) means to spectrophotometrically detect transmitted or reflected radiation from said specmen; and    i) means for correlating said detected radiation to determine the concentration of at least one interferent in said specimen.    
     
     
         2 . The apparatus of  claim 1  wherein said specimen is one of the group consisting of blood, serum, plasma or urine.  
     
     
         3 . The apparatus of  claim 1  wherein said first radiation source is comprised of a linear array of LEDs disposed along one side of said axis of said container and said first radiation detector is comprised of a corresponding array of silicon detectors on the opposite side of the container to collect transmitted radiation and wherein a spectrophotometer provides the second radiation source and detectors.  
     
     
         4 . The apparatus of  claim 1  further comprising one or more lenses to focus said radiation from said first radiation source to spread said radiation across said axis of said container) and further wherein said apparatus contains one or more further lenses which collect transmitted or reflected radiation from said specimen and direct it to said spectrophotometric radiation detector.  
     
     
         5 . The apparatus of  claim 3  or  4  wherein said specimen container contains a sample identification label on the exterior surface of said container.  
     
     
         6 . The apparatus of  claim 3  or  4  wherein said first radiation and radiation from said spectrophotometer is transmitted through a label, a container and a specimen.  
     
     
         7 . A method for monitoring specimens before said specimens are presented for clinical analysis comprising the steps of: 
 a) placing a specimen in a specimen container;    b) placing said specimen container into a holding means;    c) applying radiation from a first radiation source to said specimen and collecting transmitted or reflected radiation from said specimen;    d) analyzing said collected radiation to determine at least one parameter about said specimen; and    e) based on results from said one or more determinatioi is, positioning said container in said holder for further analysis wherein said further analysis comprises the steps of: 
 (i) spectrophotometrically applying radiation from a second radiation source to said specimen and detecting transmitted or reflected radiation from said specimen; and  
 (ii) correlating said spectrophotometrically detected radiation to determine the concentration of at least one interferent in said specimen.  
   
     
     
         8 . The method of  claim 7  wherein said container has a longiWdinal axis and said radiation from said first radiation source is focussed through one or more lenses to spread said radiation across said axis of said container, said radiation being transmitted through said container and wherein reflected or transmitted radiation from said container is passed through one or more lenses and thereby directed to said radiation detector.  
     
     
         9 . The method of  claim 7  wherein said container has a longitudinal axis and said radiation from said first radiation source is applied through a linear array of LEDs disposed along on one side of said axis of said container and said transmitted or reflected radiation is collected by a corresponding array of silicon detectors on the opposite side of said container.  
     
     
         10 . The method of  claim 8  or  9  wherein said specimen is one of the group consisting of blood, serum, plasma or urine.  
     
     
         11 . The method of  claim 8  or  9  where said specimen container contains a sample identification label on the exterior surface of said container and said radiation from said first and second radiation sources is transmitted through said label, container and specimen.  
     
     
         12 . The method of  claim 8  or  9  wherein a bar code is present on said container and said bar code is read to identify said specimen.  
     
     
         13 . The method of  claim 7 ,  8  or  9  wherein the parameter determined is one or more of the group consisting of a gel level, the thickness of said gel, the height of fluid above said gel, and the volume of fluid above said gel.  
     
     
         14 . The method of  claim 7 ,  8  or  9  wherein said spectrophotometrically detected radiation is used to determine the concentration of one or more of the group consisting of hemoglobin, total bilirubin, unconjugated bilirubin, conjugated bilirubin, delta bilirubin, biliverdin, and lipid.  
     
     
         15 . The method of  claim 14  wherein said spectrophotometrically detected radiation is used to determine the temperature of said specimen.  
     
     
         16 . The method of  claim 14  wherein said spectrophotometrically detected radiation is used to determine the type of said specimen.  
     
     
         17 . A method for monitoring blood specimens in S'P-ecimen containers before said specimens are presented for clinical analysis comprising the steps of: 
 a) reading any bar code on said container;    b) determining the location of a gel level of said specimen and the height of any fluid located above said gel    c) on the basis of said determination positioning said container such that spectral data can be obtained; and    d) interpreting said spectral data to determine the concentration of one or more intereferents, and specimen type and specimen temperature.    
     
     
         18 . The method of  claim 17  wherein said determinations are made when said container has a label on the exterior surface of said container and said determinations are made through said label.  
     
     
         19 . The method of  claim 17  wherein said interferents are selected from the group consisting of hemoglobin, total bilirubin, unconjugated bilirubin, conjugated bilirubin, delta bilirubin, biliverdin, and lipid.  
     
     
         20 . A method of determining the hematocrit of a blood sample comprising the steps of: 
 a) centrifuging a whole blood sample in a tube having an axis, to separate the sample into two phases, one being the blood cells and the other the serum or plasma;    b) while maintaining said phases separate, optically scanning the phases in said tube along said tube axis to determine a length of said axis that each of said phases occupies;    c) calculating the ratio of the axis length amounts of the cellular phase and of the serum or plasma phase; and    d) converting said ratio to hematocrit value.