STK, MTK, DGUV V3: What Is the Difference? Simply Explained
Three types of testing, three legal frameworks — the complete comparison with table
Why many operators confuse these three types of testing
STK, MTK and DGUV V3 — three abbreviations that are constantly mixed up in practice. This is understandable: all three relate to device testing, all three are legally mandated, and for some devices the requirements overlap. However, the legal bases, testing objectives and tester qualifications differ fundamentally.
In this article, we explain the differences clearly and concisely — with a comprehensive comparison table and practical examples.
The comprehensive comparison table: STK vs. MTK vs. DGUV V3
| Criterion | STK | MTK | DGUV V3 |
|---|---|---|---|
| Full name | Sicherheitstechnische Kontrolle (Safety Technical Inspection) | Messtechnische Kontrolle (Metrological Inspection) | Testing per DGUV Vorschrift 3 |
| Legal basis | Section 11 MPBetreibV | Section 14 MPBetreibV | DGUV Vorschrift 3 (accident prevention) |
| Purpose | Safety of the medical device | Measurement accuracy | Electrical safety |
| Devices | Annex 1 medical devices | Annex 2 medical devices | ALL electrical equipment |
| Intervals | Every 2 years (or shorter per manufacturer) | 1–2 years (depending on device type) | 6–24 months (risk assessment) |
| Tester | Qualified person per Section 5 MPBetreibV | Notified bodies only | Qualified electrician / competent person |
| What is measured? | Visual inspection, electrical measurements, functional test | Measurement deviation, calibration | Protective earth, insulation, leakage currents |
| Testing standard | DIN EN 62353 / manufacturer specifications | Device-specific standards | DIN EN 62353 (medical) / DIN VDE 0701-0702 (general) |
STK in detail: Safety Technical Inspection
Legal basis: Section 11 MPBetreibV
The Safety Technical Inspection (STK) is regulated in Section 11 of the Medical Devices Operator Ordinance. It serves to verify the safety of medical devices and must be carried out at regular intervals.
Which devices does the STK apply to?
The STK applies to all medical devices listed in Annex 1 of the MPBetreibV. These include, among others:
- Defibrillators
- Infusion pumps and syringe pumps
- Ventilators
- High-frequency surgical devices
- Electrical stimulation devices (with hazardous output values)
- Infant incubators
- External pacemakers
Testing interval and tester qualification
The STK must be carried out at least every 2 years — unless the manufacturer prescribes shorter intervals. Testers must meet the requirements of Section 5 MPBetreibV: suitable training, relevant professional experience, independence and appropriate testing equipment.
MTK in detail: Metrological Inspection
Legal basis: Section 14 MPBetreibV
The Metrological Inspection (MTK) verifies the measurement accuracy of medical devices with a measuring function. It is regulated in Section 14 MPBetreibV and applies to devices listed in Annex 2.
Which devices does the MTK apply to?
Typical Annex 2 devices include:
- Blood pressure monitors (non-invasive)
- Medical scales (personal scales, infant scales)
- Medical thermometers
- Tonometers
- Audiometers
- Therapy dosimeters
Important: MTK only by notified bodies
Unlike STK and DGUV V3, the MTK may only be performed by so-called notified bodies. These are specialised organisations registered with the competent authority. A standard testing service provider or qualified electrician may not perform an MTK.
DGUV V3 in detail: Electrical safety testing
Legal basis: Accident prevention regulation
DGUV Vorschrift 3 (formerly BGV A3) is an accident prevention regulation of the German Social Accident Insurance. It obliges every employer to have all electrical equipment tested regularly — from the kettle in the kitchen to the high-frequency surgical device in the operating theatre.
Which devices does DGUV V3 apply to?
DGUV Vorschrift 3 applies to all electrical devices without exception in the workplace:
- ✓ Medical devices (testing per DIN EN 62353)
- ✓ Cosmetic devices (testing per DIN VDE 0701-0702)
- ✓ Office equipment (computers, printers, monitors)
- ✓ Kitchen appliances (coffee machine, refrigerator)
- ✓ Extension leads and power strips
Testing intervals under DGUV V3
Testing intervals are based on the risk assessment and device type. Typical guidelines:
| Device type | Recommended interval |
|---|---|
| Fixed equipment (e.g. steriliser) | 12–24 months |
| Portable equipment | 6–12 months |
| Equipment on construction sites | 3–6 months |
| Medical devices (DIN EN 62353) | 12–24 months |
Why many devices require multiple tests
A common misconception: many operators believe that one test is sufficient. In practice, however, numerous devices require multiple tests. An example:
Example: Defibrillator
A defibrillator is an Annex 1 medical device and simultaneously an electrical piece of equipment. It requires:
- STK per Section 11 MPBetreibV — every 2 years (safety)
- DGUV V3 / DIN EN 62353 — 12–24 months (electrical safety)
In practice, STK and DGUV V3 testing can be combined in a single appointment.
Further examples of devices requiring multiple tests:
- Infusion pump: STK + DGUV V3
- Blood pressure monitor: MTK + DGUV V3
- Medical scale: MTK + DGUV V3
- Ventilator: STK + DGUV V3
What we offer — and what we do not
Transparency is important to us. That is why we clearly communicate which tests we perform and which we do not:
- ✓ STK — Safety Technical Inspection per Section 11 MPBetreibV: Yes, we offer this
- ✓ DGUV V3 / DIN EN 62353 — Electrical safety testing: Yes, we offer this
- ✓ MTK — Metrological Inspection: No, this is outside our scope of services. MTK may only be performed by notified bodies. We are happy to refer you to an appropriate provider.
The advantage: STK and DGUV V3 in one appointment
For devices that require both an STK and a DGUV V3 test, we offer the combination in a single on-site appointment. This saves you:
- ✓ Time: Only one appointment instead of two separate visits
- ✓ Costs: A combined test is more cost-effective than two individual tests
- ✓ Downtime: Devices are only briefly unavailable once
STK + DGUV V3 in one appointment
We perform STK and DGUV V3 in a single on-site appointment — saving you time and money. You receive separate test reports for both test types, which you can directly incorporate into your medical device log.