What Is Good Quality?

Definition of Quality

What is quality? In the medical device industry, the ISO 9000 series, which is widely used internationally, defines quality as follows:

“The degree to which a collection of inherent characteristics fulfills requirements”

From this definition, it becomes clear that quality is a relative concept of whether “a product or service conforms to customer requirements.” In other words, the state in which customer requirements and product specifications align is considered “good quality.”

On the other hand, evaluations related to usability such as “easy to use” or “difficult to use” should, in principle, be distinguished from the concept of quality itself. However, it is important to note that in the case of medical devices, if usability is included in the required specifications, it becomes subject to quality evaluation.

Learning from the Surgical Scalpel and Knife Example

Let us explain with a concrete example. Consider a situation where a surgical scalpel is needed during an operation. (This would never actually happen in practice.) Suppose, by necessity, you purchase a high-quality premium knife as a substitute for the scalpel.

Certainly, this knife may have excellent materials and precision in craftsmanship, making it high quality as a blade. However, this knife cannot be used in surgery. Why not? Because the knife does not conform to its intended use in the context of surgery.

When a medical device’s specifications do not conform to its intended use, the risk of serious accidents occurring increases significantly. A tool inappropriate for surgery, no matter how outstanding its quality as a general product, cannot be said to have good quality as a medical device.

The Screwdriver and Screw Example

Consider another example. Imagine you need to fasten a Phillips screw but cannot find a Phillips screwdriver. Technically, it is possible to fasten a Phillips screw with a flat-head screwdriver. In some cases, you may actually succeed in fastening it.

However, if you repeatedly fasten Phillips screws with a flat-head screwdriver, the corners of the screw hole may become stripped or damaged. Moreover, repeated use can cause damage to the tip of the screwdriver itself. In other words, a flat-head screwdriver does not conform to the intended use of fastening Phillips screws reliably and safely. Such usage methods increase the risk of accidents or failures.

Fitness for Purpose

A critical concept in medical device regulation is “fitness for purpose.” This approach does not merely evaluate the inherent, intrinsic quality of the medical device itself alone. Rather, it evaluates whether the device’s specifications appropriately conform to the actual conditions of use in healthcare settings, the characteristics of the patient population, and the methods of use by users (such as healthcare professionals and patients).

In medical device regulation, the intent is not to regulate only the intrinsic quality of the medical device itself. What matters is whether the device’s specifications align appropriately with how it will actually be used in healthcare settings, by patients, and by other users.

When a medical device’s specifications do not conform to its intended use, the risk of accidents is inherent from the design stage. In such cases, the medical device cannot be said to have good quality.

Quality Management in Regulatory Requirements

International standards such as ISO 13485 (Quality Management System for Medical Devices) and IEC 62304 (Medical Device Software Development Processes), as well as medical device regulations in each country (FDA 21 CFR Part 11, EU MDR, PMDA guidance, etc.), require the establishment of quality management systems to ensure this “conformance to required specifications.”

From the clarification of required specifications in the design and development stage, through the management of manufacturing processes, to post-market surveillance, the essence of quality management is to continuously confirm and maintain alignment between “customer requirements” and “actual product performance.”

Conclusion

Good quality is not merely about the intrinsic excellence of a product. Rather, it is first and foremost defined by whether “the specifications conform to the intended use.” For medical devices, where safety is critically important, this concept of “fitness for purpose” becomes especially significant.