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Rann Card

BBI Rann Card

The Rann card has been developed by BBI as a means to assess signal intensity of gold based lateral flow based assays.

The Rann card was introduced to effectively replace more subjective measures such as +, ++, +++ scoring systems and is currently used as both a tool for development and as a control tool to facilitate consistency during the manufacturing process for lateral flow products.

image of a Rann card and the scoring system

Where signal intensities fall between scores lines an intermediate score is assigned as appropriate i.e. 1, 3, 5, 7 or 9.

Rann cards are produced by spraying gold conjugate at increasing concentrations to yield a range of line intensities.  Test results obtained from running the lateral flow assay can then be visually compared and ‘scored’ against the card by the operator.

Rann Card Benefits

  • A less subjective assessment of test line intensity than many other methods is provided
  • Acts as a more consistent reference for use between operators / sites
  • Training and training verification of signal intensity assessment is facilitated

Rann Card Limitations

  • The scoring process remains subjective under different environmental conditions and between operators
  • The scoring process is not considered quantitative
  • Statistical analysis of Rann scores is problematic due to the non-continuous nature of the scoring data and its inherent subjectivity and variation
  • Rann cards have been given a 2 year expiry date. Beyond this date the performance of the card cannot be guaranteed

Recommendations for Use

  • Assay signal intensity assessments during development
  • Manufacturing consistency control and trending
  • Not recommended for quantitative analysis / formal product release specifications

(Reader systems are recommended for quantitative assessments)

  • It is the end user’s responsibility to check the expiry date of the Rann card and request new Rann cards as and when required

BBI’s ongoing use of Rann cards is aligned with the above and use for any given application is verified and qualified appropriately.

It is recommended that Customers adhere to these guidelines and that any process use of Rann cards be appropriately qualified.

For more information, please contact us.

BBI Solutions Brands


The acquisition of DIARECT in June 2020 and their world leading recombinant autoimmune antigen capability immediately enhances BBI’s portfolio and position as a ‘complete’ immunoassay reagent supplier. This further enhances BBI’s position as the world’s largest diagnostics components company with a market leading antigen portfolio.


Maine Biotechnology Services brings 27 years of knowledge, experience, process development, and project management to our customers to ensure the best possible antibodies for any application. As antibody development goals in the biotechnology and pharmaceutical industry have evolved the acquisition of MBS will help BBI further meet and exceed our customers needs.


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