Rapid Microbiological Method or Conventional Method? What Should You Use?

In the get-it-done-yesterday environment companies are finding that the traditional microbiological methodologies and especially sending microbiological samples to outside labs cost them time, money and opportunities1.  Internalizing the microbiology testing and especially adopting rapid microbiological methods (RMM) can significantly speed up the time to results from 7-10 days to 24-48 hours.  The time saved creates opportunities for faster response to contamination, quicker product release, faster delivery of product to the marketplace, reduced warehouse space, and enhanced product quality.  Advantages of RMM can include: Greater accuracy, better sensitivity, increased sample throughput, automated data capturing allowing easier data handling, and reduced cost for product release.

However, like any other investment it competes for company resources.  Therefore, there is a need to calculate the financial benefits of the investment in RMM.

Dr. M. Miller, an authority on RMM, has written extensively on this topic and suggests that before adopting a new RMM or internalizing Microbiology the key steps required include2, 3, 4:

  1. Review of existing technologies
  2. Understand the technical and financial benefits of RMM
  3. Develop the business case for RMM

This will include the use of financial models that can compare the overall costs associated with the current microbiology method with the costs and savings associated with the purchase, qualification, and implementation of the RMM

Return on Investment (ROI)

ROI is the ratio of money gained or lost on an investment relative to the amount of money invested.  According to Dr. Miller3 for RMMs, the cost of performing the conventional method (CM) is compared with the cost (and savings) of using the new method. The information is reported as a percentage and usually represents an annual or annualized rate of return. The ROI is calculated using the following formula4:

CM costs can include:  cost of consumable; reagents and supplies; sample preparation time; data management documentation and record retention time; as well as cost of labor and overhead.

Potential investment in RMM can include:  Capital cost; and validation cost.

Potential cost savings of RMM can include:  Reduced time for product release; Lower headcount; lower re-processing fees; reduction in plant downtime; increased production yields; reduced raw materials, in-process and finished products inventory holding; reduction in back orders; increased production flexibility; and better protection of company image.

Payback Period (PP)

The PP is the time required for the return on an investment to “repay” the sum of the original investment. In the context of implementing an RMM, this would be the time (usually in years) required to realize sufficient cost savings to pay for the initial investment of the RMM capital equipment as well as for qualification and implementation activities3, 4.

Requirements from RMM

While Rapid Microbiological Methods (RMM) offer high degree of automation, significant reduction in time to results, faster product release, ability to employ non-microbiologists to operate the system, and improved control; there are three basic objectives that must be meet:

  1. Comply with FDA and cGMP regulations
  2. The RMM must be validated against the standard USP methodology using a protocol similar to USP <1223>.
  3. Ensure a swift return on investment.

Additionally, the ideal system should be capable of:

  1. Performing all the microbiological assays required to be performed by lab on a single platform.
  2. The technology should eliminate or at least minimize any product interference.
  3. Allow for a paperless microbiology laboratory-allowing the laboratory to operate without handwritten data entries
  4. Automate the system reporting
  5. Real-time communication to locations outside the lab to provide early warning of contamination

Required Commitment from RMM Vendors


To make the transition to a rapid method the vendor should help in the system validation to make the transition to the new system smooth and “painless”. It should include Installation Qualification (IQ); Operational Qualification (OQ), and help with the Performance Qualification (PQ). PQ is the most extensive portion of the validation and sometimes companies considering RMM are deterred by the amount of work required for validation. Vendors can generated most of the data and submit it to the FDA in a form of a DMF.  The same information can be supplied to new users together with unique data pertaining to their products.


The software must be compliant with 21 CFR Part 11.  21 CFR Part 11 regulations are established requirements to ensure that electronic records and electronic signatures are trustworthy, reliable and generally equivalent substitutes for paper records and traditional handwritten signatures. Any instrument system containing software must be compliant with this regulation.

Technical Support:

Instruments suppliers should guaranty live technical service that is fast, knowledgeable, and readily available.

The BioLumix system is an example of a system that fulfills the requirements listed above.  Its straightforward streamlined design offers rapid accurate results leading to reduced material-holding time for faster product release.  Early warning of contaminated samples as well as sample release information could be automatically communicated through your intranet, significantly improving your company’s efficiencies.

To evaluate the value proposition of RMM systems BioLumix offers a free assessment of your specific ROI and Payback Period.  This will help you determine whether there are sufficient cost benefits of adopting a RMM system.  Past ROI calculations demonstrated that in many situations the ROI obtained showed that a RMM, like the BioLumix system, improved the company’s bottom line and satisfied the financial expectations of site management.


  1. 2009. Gadal, P.; Yvon, P. Rapid Microbio ROI – Calculating scientific benefits as return on investment dollars. Pharmaceutical Formulation & Quality. 11(3): 44-47.
  2. 2009. Miller, M.J. Breaking the rapid microbiological method financial barrier: A case study in RMM return on investment and economic justification. BioPharm International. 22(9): 44-53.
  3. 2009. Miller, M.J. Ensuring ROI from your RMM. Pharmaceutical Manufacturing. 8(6): 32-35.
  4. http://rapidmicromethods.com/files/roi.html
  5. USP <1223> Validation of Alternative Microbiological Methods.

Ruth Eden, PhD


BioLumix. Inc.

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