Prolex® "New" and "Blue", developed by Pro-Lab Diagnostics, offers a breakthrough in routine streptococcal grouping. Results can now be obtained instantly at room temperature for all six clinically significant Lancefield group streptococci including group D.

Classification of beta haemolytic streptococci into serogroups based upon cell wall antigenic polysaccharides was first described by Lancefield (1933). Each 'Lancefield '' Group was described by a letter, however only a few are clinically significant in the field of human diagnostic microbiology, these being Lancefield groups A, B,C,D,F and G.

The identification of these clinically significant Lancefield groups forms an integral part of the routine microbiology carried out in today's busy diagnostic testing laboratories. With increasing pressure for results to be made available faster, whilst maintaining specificity and sensitivity, Pro-Lab Diagnostics is dedicated to researching this area.

The identification of clinically significant streptococci and their group specific carbohydrate antigens has traditionally been demonstrated by a number of techniques including group specific precipitation, fluorescent antibody sera and agglutination tests with antigen extracted from organisms using enzymes. This latter method became common in numerous laboratories offering results after 20-30 minutes incubation at 37°C. An alternative to the enzyme extraction procedure was to use Nitrous Acid extraction. This offered the advantage of speed, whilst reducing the incubation time to only a few minutes, and could be carried out at room temperature. A disadvantage of this method was its' inability to identify D antigen in streptococci or enterococci, and concerns were also raised over the use of Nitrous acid.

The Prolex® "New" and "Blue", breakthrough has been made possible by the development of a unique set of modified acid extraction reagents. Following a simple instant extraction procedure at room temperature, results are clearly visible when the extracted carbohydrate antigen is mixed with specific antibody coated latex particles. As the name of the kit suggests, the coated latex particles also harbours new innovations. The use of specific sized blue carboxylated latex particles, coated with antibody using a proprietary technique, offers clearer and faster agglutination reactions against a white background.

Prolex® "New" and "Blue" is available in kit format, as single reagents, or as custom designed kits allowing customers to select the groups required.

Streptococcal grouping has changed, samples and introductory demonstrations being available on request. Full clinical trial data is available on request from Pro-Lab Diagnostics.

email: prolexblue@pro-lab.com