Photosedimentation Technology from Cytotech

[Rob48]

An old colleague from Russia told me about the Photosedimentation Technology based instrument from Cytotech for Red Cell Serology. He said it is very popular in that part of the world.Has anyone else in the forum used it?

[bloodbanker84]

I have seen it being used in some centres in UK. Seemed preety good...though I dont have the details.

[Eva Szego]

I have come across your message about Cytotech and its photosedimentation based products just now. These products are still on the market together with a new development, a fully automatic robot. Cytotech is a Hungarian company. I hope this was not advertising.

[Agnes FRISS]

An old colleague from Russia told me about the Photosedimentation Technology based instrument from Cytotech for Red Cell Serology. He said it is very popular in that part of the world.Has anyone else in the forum used it?

I had used the ACT-24 for more than 20 years, from early 90's till 2009. Now as a retiree I use it in a first (lowest) level blood group laboratory. For the first 10 years we worked with it in the Central Military Hospital's Laboratory, used it for routine antibody screening and identification. It was a reliable instrument. From 2004 as a head of the Immunohematology Reference Laboratory of the National Blood Transfusion Service I used it for comparative tests. Compared were the microplate and column agglutination techniques with this automated tube technique. In several thousands of tests the photosedimentation technique proved to be as sensitive as the column agglutination and slightly more sensitive than the microplate technique. The specificity was about the same.

The ACT-24 provides a more cumbersome procedure than the column agglutination, for it does the classical antiglobulin test, inlcuding the washes, on the other hand it is much cheaper and much more flexible: you can vary the proportion of the test participants, use more or less red cells, AHG, etc. It is also possible to use various brands and qualities of reagents.

In my present laboratory we use it also for antibody screening and ABO+D typing. This last feature contains the evaluation of the blood group, too.

[galvania]

How does it work?

[Agnes FRISS]

The method's principle is that agglutinated cells sediment more quickly than free cells. The bigger the agglutinate the quicker the sedimentation. A photometer measures the rate of the centrifuged cell suspensions. The non-agglutinated cells give a characteristic sedimentation curve as do the variously agglutinated cells. The curves are calibrated, the results can be visualized traditionally as -, +, ++, +++, ++++ or according to Marsh on a scale from 1 to 12.

In the last years there has been added a new feature: a photo is made of each tube and the evaluation is based on the photo + the sedimentation curve.

Agnes

[galvania]

And what do you pipette into? Sorry for my ignorance but in 40 years I've never heard of this before!

[Agnes FRISS]

There are special curved tubes, that is what gets pipetted into. Do not be ashamed, the ACT is produced by a small firm, always in need of capital.