MEASURE FOR MEASURE
Calibration, From Cradle to Grave
Equipment operating outside of limits shouldn’t be tolerated
by Jay L. Bucher
The phrase in the headline is one commonly used in drug development. But it makes just as much sense when talking about calibration, because in nearly every part of our lives, we are exposed to various measurement disciplines and influences.
This starts almost from conception. Condoms, at-home pregnancy tests and birth control pills—how accurate, safe and reliable are they? Are the instruments and measurements used to test, qualify and certify them calibrated to a national or international standard?
Is a product that falls outside of specifications not something for anyone to get excited about? Sonograms aren’t really that important, are they? They’re just pictures, and what difference does it make if you can tell if it’s a boy or a girl, anyway? It’s too late to change it, so who cares? And all those tests that tell the proud parents if their unborn child has birth defects of one kind or another—those aren’t really important, are they?
All of the previously mentioned events are, of course, important and, in some cases, critical. Modern medicine has come far since the days of throwing bones in a bowl or reading tea leaves. But modern medicine would be decades behind if not for the use of traceable, calibrated test instruments.
We’re all weighed and measured shortly after birth. How do you know the weight is accurate? Was the scale calibrated on a regular basis? Was a calibration procedure used? Was the standard weight used during calibration traceable to a national or international standard? Is there a paper trail on hand somewhere to prove this, or do we just take somebody’s word for it?
What did they use to measure the baby’s length? Was it a tape measure from a hardware store or just a yardstick screwed to the table? A baby has barely taken its first breaths, and it might already be time to wonder if a quality calibration program is in place at the hospital. Not a good sign, folks. There should be no wondering involved. It should be a given at every hospital and clinic.
Not just for kids
It doesn’t stop with the newborn. The last time you went to the doctor’s office, did they take your weight and your blood pressure? They do that to me every time I go, but I never can find a calibration label on the scale or sphygmomanometer.
If the scale is off by as little as five pounds, it could mean the difference between being classified as obese or being considered healthy for my height and weight. The same is true for my blood pressure. I could actually be in the safety zone but, because of faulty calibration, wind up on medication.
Like so many things in life, we take a lot for granted that could cost us time, money and quite possibly our health. We all assume, and rightly so, that all of the prescribed medications taken every day by millions of Americans are safe for human consumption. Even the over-the-counter (OTC) drugs need to meet some sort of standard. When you take an aspirin, sleep medication or prescription drug, how do you know each pill is providing you with the exact same dosage?
Nothing is exact (ask any anal-retentive metrologist or calibration technician), but OTC and prescription drugs must meet a certain specification for the ingredients in each pill. If they didn’t, then one pill might have no effect, while another from the same bottle causes an overdose. I don’t believe we have that problem with our OTC or prescription drugs because of the calibration of the test equipment used.
Isn’t that why the Food and Drug Administration is such a major part of the U.S. landscape? Of the $14 trillion U.S. gross domestic product, the FDA is involved in approximately 25%—or about $3.5 trillion.
The FDA’s requirements—the quality system regulation (QSR)—are the most stringent regulations to which a manufacturer can be held. The general calibration portion of the QSR is found in the code of federal regulations (CFR), more specifically 21 CFR, Part 820. It’s important to keep in mind that it is, in fact, a regulation, not a standard, which is voluntary.
Among other things, that portion of the QSR (found in Part 820.72) states that:
- Manufacturers establish procedures to ensure equipment is routinely calibrated, inspected and maintained, and that those activities are documented.
- Calibration procedures include directions and limits for accuracy and precision. When those limits are not met, action is taken to re-establish the limits and evaluate whether there was any adverse effect on the device’s quality.
- Calibration standards are traceable to national or international standards. If no standard exists, an in-house standard is established and maintained.
- The equipment ID, calibration dates, the individual performing each calibration and the next calibration date are documented and readily available to the personnel using the equipment and the individuals responsible for calibrating it.
Now that you know what’s included in the regulation, how do you apply it to your particular situation? The basic premise of a quality calibration program is this:
- Say what you do (write calibration procedures).
- Do what you say (follow your calibration procedures during each and every calibration).
- Record what you did (record what your calibration standard read, as well as the "as found" and "as left" readings of the item being calibrated).
- Check the results (make sure the test instrument being calibrated falls within its stated tolerances).
- Act on the difference (if the test instrument was out of tolerance, remedy the situation).
You do not have to fall under the purview of the FDA to need a quality calibration program. Every time a company makes a quantitative measurement using test equipment, that equipment requires calibration. And the same quality calibration program needed to meet FDA regulations is the same program that could be used by any company, anywhere, at any time.
It costs no more to have a quality calibration program than it does to have a regular calibration program. But it does cost more to have an inadequate calibration program because of the poor quality that can lead to recalls, damage to reputation and loss of customers.
A daily occurance
The reach of calibration extends into our everyday lives. Take the simple act of listening to music. It doesn’t matter what type you prefer; if your radio, iPod, television or satellite isn’t functioning, you might as well be playing a jug and washboard. If calibrated instruments are not used in the manufacture and tuning of critical items used throughout the industry, then we cannot transmit, receive or enjoy music of any variety.
Another example of old versus new calibration technology is the difference between using a Gunter’s chain (also known as a survey chain, the Gunter’s chain was designed and introduced in 1620, and is 66 feet), and today’s Global Positioning System surveying equipment.
During a recent snowstorm where I live in Wisconsin (we exceeded 100 inches in Madison this winter), I observed a surveyor unloading a four-wheeler from his truck and doing a survey of the land across from my house during a near-blizzard. I asked him afterward about the technology and accuracy. He said the survey was accurate within inches, and his equipment was calibrated yearly. It didn’t matter how far he could see; he knew exactly where he was at all times.
Calibration has been around for at least 5,000 years—stretching back to the days of the Egyptian cubit—and will continue to be a critical part of every manufacturing, production and R&D function for as long as measurements are needed.
The quality of your calibration program will help determine if your customers come back for more of what you make or go looking for other suppliers who are willing to provide quality products that make our lives longer, easier and more enjoyable.
JAY L. BUCHER is president of Bucherview Metrology Services, LLC, a consulting company specializing in quality calibration systems. He is co-author and editor of The Metrology Handbook, and author of The Quality Calibration Handbook and Paperless Records—Designing and Creating Your Own Electronic Forms. He is a senior member of ASQ, the treasurer of the ASQ Measurement Quality Division and a certifi ed calibration technician.