Sensitometers and densitometers must be recalibrated periodically to insure accuracy. As a further check on the consistency of field sensitometers between calibrations, we are asking each inspector to compare his/her sensitometer readings with other FDA-MQSA calibrated sensitometers on a monthly basis. Records of these sensitometer checks should be maintained by each inspector.
When there are two or more MQSA inspectors at a single location:
- When you leave to go inspect a facility, bring along as many sensitometers as is reasonable for comparison.
- Flash the sensitometers as follows:
(a) In rapid succession
(b) All with the same film (FDA provided control film)
(c) Process each film in rapid succession in the same processor
(d) Read all the films with the same densitometer
- If (and only if) the difference in the optical density readings at step-11 is equal to or larger than 0.1 between any two sensitometers, repeat the test. If the same results are obtained, please notify DMQS.
(a) Notify DMQS through MPRIS E-Mail.
(b) Please include in the E-Mail message the following information for each sensitometer tested:
1) Name of inspector
2) Inspector ID number
3) Sensitometer serial number (date of last calibration)
4) Optical Density at step-1, step-10, step-11, step-12, and step-13
5) Date of comparison testing and other sensitometers tested
Date: November 16, 1995
Name/ID# Serial # 1 10 11 12 13
John Doe(9534) #14958 0.19 0.45 0.84 1.43 2.04
Bob Doe(7483) #13494 0.19 0.45 0.85 1.46 2.07
Jane Doe(8744) #23404 0.19 0.56 0.95 1.56 2.18
Note: For this example, for step-11 the 1 optical densities are 0.84, 0.85, and 0.95. Jane Doe's sensitometer (#23404) should be retested. If the density difference continues to be 0.10 or greater after the retest, contact DMQS for further instructions before using sensitometer #23404 during an inspection.
When you are the only MQSA inspector in a particular region, without easy access to another inspector's FDA-MQSA equipment:
- Contact DMQS through MPRIS E-Mail.
- We will try to provide you or your region with a second sensitometer for you to compare against.
Note: It is always important to periodically check the densitometer against the calbration strip that is provided with the inspector equipment.