| 
   % Diff, (Mean(Stored)-Mean(Fresh))/Mean(Fresh)×100
  | Peak Area Ratio (n=3) |  
  | Validation samples | 24 hours | 96 hours |  
  | Fresh | Stored | %Diff | Fresh | Stored | %Diff |  
  | 2 pmol/106 cells | Mean | 0.04374 | 0.04120 | −5.8 | 0.04126 | 0.03827 | −7.3 |  
  | SD | 0.00193 | 0.00159 |  | 0.00362 | 0.00297 |  |  
  | CV% | 4.4 | 3.9 |  | 8.8 | 7.8 |  |  
  | 200 pmol/106    cells | Mean | 4.22040 | 4.18034 | −0.9 | 3.99101 | 4.12102 | 3.3 |  
  | SD | 0.04920 | 0.12610 |  | 0.13888 | 0.07118 |  |  
  | CV% | 1.2 | 3.0 |  | 3.5 | 1.7 |  |  |