Is there a way to convert the units used on SRB Rapid Check II (cell/mL) to the units used on Hach SRB BARTs (cfu/mL)?

Document ID

Document ID TE1756

Version

Version 2.0

Status

Status Published

Published Date

Published Date 27/05/2017
Question
Is there a way to convert the units used on SRB Rapid Check II (cell/mL) to the units used on Hach SRB BARTs (cfu/mL)?
Summary
Conversion from cell/mL to cfu/mL
Answer
No - there is no way to convert these measurements unless you know what % of the SRB cells will form colonies (depends on cell type, environment, nutrients, etc). A colony is a group of cells that all derive from the repeated divisions of single parent cells. After letting a dilute sample in a BART grow over 8 days, the cells begin to multiply and form colonies in the BART. The BART is semi-quantitative, but is very sensitive. It will detect between anaerobic and aerobic SRB which is important for process control.

The SRB Rapid Check II uses an immunoassay method. Antibodies are attached to small particles that selectively capture the APS reductase enzyme. These particles and the captured enzyme are then isolated on a porous membran, forming a reactive layer. The layer then becomes blue in the presence of a chromagen, indicating the presence of the PAS reductase enzyme. Darker shades of blue indicate a higher number of SRB. Each batch of reagents is calibrated to match known SRB quantities with distinct shades of blue color. Since this is dependent on a specific amount of SRB cells the results are given in cells/mL. This test is more "quantitative," but is not as sensitive as the BART test.