Method and device for identification of nucleated red blood cells from a maternal blood sample

Abstract

A method for concentrating and isolating nucleated cells, such as maternal and fetal nucleated red blood cells (NRBC's), in a maternal whole blood sample. The invention also provides methods and apparatus for preparing to analyze and analyzing the sample for identification of fetal genetic material as part of prenatal genetic testing. The invention also pertains to methods and apparatus for discriminating fetal nucleated red blood cells from maternal nucleated red blood cells obtained from a blood sample taken from a pregnant woman.

What is claimed is: 
     
         1 . A method of creating a layer of cells on a surface including the following steps:
 moving with a smear tool a sample of cells in at least two directions relative to a surface to thereby create a monolayer of the cells on the surface; and   adhering the cells to the surface.   
     
     
         2 . The method of  claim 1  wherein moving the cells comprises moving the smear tool in at least one of a circular movement, a zigzag movement, a diagonal movement, and a serpentine movement relative to the surface. 
     
     
         3 . The method of  claim 1  wherein moving further comprises moving a portion of the sample away from the surface. 
     
     
         4 . The method of  claim 1  wherein moving comprises varying an angle of the tool with respect to the surface. 
     
     
         5 . The method of  claim 1  wherein moving comprises varying the relative speed of the tool with respect to the surface. 
     
     
         6 . The method of  claim 5  wherein varying comprises varying the relative speed in the range of 0.1 mm/sec to 500 mm/sec. 
     
     
         7 . The method of  claim 1  wherein moving further comprises the step of generating a generally uniform sample density. 
     
     
         8 . The method of  claim 1  wherein moving further comprises the step of monitoring the density of the sample relative to the surface. 
     
     
         9 . The method of  claim 1  wherein moving further comprises the step of monitoring the density of the sample relative to the surface using red light. 
     
     
         10 . The method of  claim 1  wherein moving further comprises the step of monitoring the density of the sample relative to the surface using blue light.