CTL Analyzer Excellence — Quality Matters!

ImmunoSpot Well Image Competitor Well Image Competitor Well Image
ImmunoSpot® well image,
664 Kb TIFF, captured
with 512x512 resolution.
Auto settings used.
Same well from same plate.
Read with competitor machine.
547 Kb TIFF.
Optimized settings used.
Another competitor image.
45 Kb JPEG, captured
with 640x480 camera.
Square format invariable.

Hardware Quality

All cameras in ImmunoSpot® Analyzers were selected for quality, durability and color performance. The optics in each Analyzer are calibrated for both single- and double-color analysis. All Analyzers use high-quality resolution color cameras.

In addition to high resolution settings, lower resolutions may be selected for spots of larger sizes as well.

Image Illumination

ImmunoSpot® Analyzers use advanced lighting systems to provide even illumination of each well. In addition, auto-light adjustment in every single well ensures that spot counting is accurate, even when the background varies strongly. Thanks to this feature, fewer parameter adjustments are necessary in the counting process.

Image Size

The ImmunoSpot® Elispot readers produce TIFF images with sizes ranging from 660 Kb to 1.600 Kb. When the analysis of very small spots is required (e.g. Granzyme B, TNF, partly IL-10), it is important to preserve as much image information as possible. Whereas some competitor systems allow the conversion of well images to JPEG files — thereby degrading the image and losing valuable information — ImmunoSpot® Analyzers preserve the image integrity by using lossless TIFF files.


Even if the well images do have the same format and the same Kb size, still the contained information can vary. Most competitor machines capture not only the well bottom, but parts of the side walls as well. This increases the image size without adding any useful spot information. In addition, mirror images of spots, reflected on the side walls, are also captured and thus contribute to imprecision in the counting process.

In contrast, the ImmunoSpot® Analyzers feature Digital Focus, which is used to capture only the membrane image. In addition, all Analyzers feature automated centering of every single well image. Intelligent software algorithms precisely determine the center of each well, and automatically place the image in the center of the area to be captured. Thanks to this feature, ImmunoSpot® Analyzers compensate for manufacturing variations in the microtiter plates. With the ImmunoSpot® software, plate scanning thus becomes a true walk-away process.