Dr. Christopher Joseph Devine, President, Devine Guidance International
Devine Guidance

Can You Say Calibration is a Basic Requirement?

By Dr. Christopher Joseph Devine
Dr. Christopher Joseph Devine, President, Devine Guidance International

What is required of an FDA compliant calibration program? How about crafting a program that actually results in inspection, measuring and test equipment actually being calibrated?

Folks, one thing that Dr. D loves to do is read FDA warning letters. Not because of the doctor being some sort of sadomasochist that loves reading about a Chief Jailable Officer’s (CJO) pain, but as a way of discovering what issues FDA is concerned about. The doctor also takes great pride and joy being able to share the misery of others with the readers in the hopes that you will not make these same mistakes. Now one thing device manufacturers can take to the proverbial bank (not the European databank) is that measuring and monitoring devices must be properly maintained and calibrated. In fact, calibration programs were premised on an old-time defense standard such as MIL-STD 45662, cancelled in February of 1995; although now in the format of ISO 10012:2003 (Measurement management systems — Requirements for measurement processes and measuring equipment) and regulatory requirements called out in §820.72 (Inspection, Measuring, and Test Equipment). Considering the calibration of inspection, measuring, and test equipment is a fundamental expectation, Dr. D was quite surprised to come across a warning letter that reflected an establishment that did not have procedures in place to ensure equipment is routinely calibrated. From an agency perspective more than a “scintilla” (look-it-up) of a procedure is warranted to support the calibration program. Not having a procedure or a program, well that is just unacceptable in the eyes of FDA. Enjoy!

Warning Letter

As stated in this week’s introduction, the doctor was surprised to come across a warning letter that cited not having established a written procedure(s) for calibration. After all, calibration is one of those quality management system (QMS) tasks that can be easily outsourced to a metrology laboratory (hopefully one that is ISO/IEC 17025:2005 accredited). If the decision is made to outsource calibration then the scripting of an SOP becomes easy; as you really need to draft just one congruent SOP while ensuring the SOP addresses the requirements nestled in §820.72 and/or Clause 7.6 of ISO 13485:2012 (Control of Monitoring and Measuring Devices). Regardless, not having an established SOP for calibration is always going to turnout badly for a medical device establishment.

Warning Letter Excerpt – 09 October 2013

Failure to establish and maintain procedures to ensure that equipment is routinely calibrated, inspected, checked, and maintained, as required by 21 CFR, 820.72(a). Specifically, your firm has not established written procedures to ensure that your (b)(4) tester, used to conduct high voltage testing on your tanning beds, is routinely calibrated and inspected annually.

The tester was observed to have been last calibrated on January 12, 2009.

You explain in your written response you will either discontinue using the (b)(4) tester or calibrate the (b)(4) tester.

Subpart G—Production and Process Controls

Sec. 820.72 Inspection, measuring, and test equipment.

(a) Control of inspection, measuring, and test equipment. Each manufacturer shall ensure that all inspection, measuring, and test equipment, including mechanical, automated, or electronic inspection and test equipment, is suitable for its intended purposes and is capable of producing valid results. Each manufacturer shall establish and maintain procedures to ensure that equipment is routinely calibrated, inspected, checked, and maintained. The procedures shall include provisions for handling, preservation, and storage of equipment, so that its accuracy and fitness for use are maintained. These activities shall be documented.

(b) Calibration. Calibration procedures shall include specific directions and limits for accuracy and precision. When accuracy and precision limits are not met, there shall be provisions for remedial action to reestablish the limits and to evaluate whether there was any adverse effect on the device’s quality. These activities shall be documented.

    1. Calibration standards. Calibration standards used for inspection, measuring, and test equipment shall be traceable to national or international standards. If national or international standards are not practical or available, the manufacturer shall use an independent reproducible standard. If no applicable standard exists, the manufacturer shall establish and maintain an in-house standard.
    2. Calibration records. The equipment identification, calibration dates, the individual performing each calibration, and the next calibration date shall be documented. These records shall be displayed on or near each piece of equipment or shall be readily available to the personnel using such equipment and to the individuals responsible for calibrating the equipment.

Calibration Program

So what is required of an FDA compliant calibration program? How about crafting a program that actually results in inspection, measuring and test equipment actually being calibrated? Yes, the doctor is being somewhat smart-alecky; however, there is some truth in Dr. D’s words. The underlying purpose of a calibration program is to ensure equipment is calibrated to a standard. Can you say NIST? 

Additionally, the equipment employed for inspection, measuring, and test must be adequately protected from damage (i.e., proper handling, preservation, and storage) to ensure it functions correctly in its intended use. Furthermore, equipment must be calibrated using written procedures that specify limits for precision and accuracy. Who knew? If equipment fails to meet precision and accuracy requirements, then remediation activities to address the nonconforming equipment must be pursued, including an investigation to determine if the nonconforming instrument may have impacted the acceptance of finished medical devices.

As previously stated, equipment must be calibrated to a standard that is traceable to a standard, and preferably a national standard, such as NIST in the United States. If a device establishment cannot provide reasonable traceability to a national standard, then creating an in-house standard may be a viable option. However, if the decision is made to pursue this path, the validation of such a standard better be rock-solid and beyond reproach.

Finally, do not forget about the records. You see, FDA likes device manufacturers to retain documented evidence of compliance. If calibration records are not being collected and/or retained, then in the eyes of FDA, the equipment has not been properly calibrated. Additionally, make sure calibration stickers containing basic information, relative to the calibration, are affixed to the inspection, measuring, and test equipment. If a piece of inspection, measuring, and test equipment is too small for a label, affix the label to the carrying case. As a minimum, the date calibrated, the calibration due date, and the person calibrating the equipment should be captured on the calibration label, along with a unique identifier (e.g., asset or equipment tag). 

If calibration is being outsourced, make sure the supplier is:

  • An accredited ISO/IEC 17025:2005 accredited facility;
  • Audited by your establishment (Dr. D recommends annual visits to kick the proverbial tires);
  • Listed on your ASL; and
  • Trained to your procedures, especially if they are performing calibration on-site (consider training these suppliers to proper gowning techniques and controlled environment requirements, safety, your organizations calibration SOP, and other SOPs, as applicable).


For this week’s guidance, the doctor will leave the readers with four takeaways. One – Consider this a Duh, Duh-Duh moment but a written procedure is required to be established for calibration. Two – If calibration work is outsourced make sure your organization employs qualified metrology laboratories accredited to ISO/IEC 17025:2005. Three – Written records, a.k.a., documented evidence, are required to support claims of compliance. Four – If calibration is performed on-site, make sure metrology contractors are trained to applicable SOPs and the training is documented; a.k.a. documented evidence of compliance.

In closing, thank you again for joining Dr. D and I hope you find value in the guidance provided. Until the next installment of DG – cheers from Dr. D. and best wishes for continued professional success. 


  1. Code of Federal Regulation. (2013, April). Title 21 Part 820: Quality system regulation.  Washington, D.C.: U. S. Government Printing Office.
  2. Devine, C. (2011). Devine guidance for complying with the FDA’s quality system regulation – 21 CFR, Part 820. Charleston, SC: Amazon.
  3. FDA’s enforcement page – warning letters. (2013, October). FDA.gov Website. Retrieved October 27, 2013, from http://www.fda.gov/ICECI/EnforcementActions/WarningLetters/2013/ucm371255.htm

About The Author

Dr. Christopher Joseph Devine, President, Devine Guidance International