The Proportionator™ is a very efficient sampling principle in stereology that uses image analysis to perform a non-uniform sampling based on the extent of the feature of interest in each field of view. 


The Proportionator™ provides the tool necessary to design an image analysis protocol to guide the sampling process. The image analysis protocol will detect the relevant feature (e.g. area of stained cells) and calculate the amount of feature, termed "weight," in all the fields of view. This can be done in many ways and the only requirement is that the content (or weight) is proportional to the count in the sampling positions.


The Proportionator™ greatly increases sampling efficiency since practically all fields of view will contain the feature of interest. Recently a comparative study* showed that the Proportionator™ was twice as fast as normal meander sampling and in combination with Visiopharm’s Autodisector™ it became three times faster (Keller et al., 2013, Improving efficiency in stereology: a study applying the proportionator and the Autodisector on virtual slides. Journal of Microscopy, 251: 68–76).


Large-scale stereology research projects now become possible with the Proportionator™. The largest increase in efficiency is on inhomogeneous tissue, like ß-islets in the pancreas or Purkinje cells in the cerebellum. However, there is always a net gain in efficiency when using Proportionator sampling.


An image analysis protocol analyses all slides from an individual, and a weight is assigned to all fields of view across slides. The fields of view are then sorted based on their weight, and the sampling is then performed within those fields. This gives a field with a high weight value a higher probability of being sampled than a field of view with a low weight. For each sampled field the weight value and the sampling probability are logged.


With systematic uniform random sampling (SURS), image analysis can now be done at high magnification allowing for the detection of very small objects that would normally be impossible to detect at a low magnification.


Visiopharm’s powerful Stereotopix™ solution, with the help of the Proportionator™, provides a complete workflow for high volume, efficient use of stereology. First, an image analysis protocol is created, guided sampling is performed, counting is done with one of the several geometric probes offered, and the calculation of the weight-corrected counting results are done automatically and presented in an excel data sheet. The unbiased estimate can then be calculated using the weight-corrected results, and the CE of the estimate can be directly calculated from the sampling data in the Calculator.

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Advantages of Proportionator™

  • Increase speed with guided sampling powered by image analysis
  • Greatly increase sampling effi ciency especially in combination with Autodisector™ and Virtual™
  • Save time, reduce expenses
  • Detect small objects effectively
  • A complete workfl ow for stereology