Control (CONTROL box)
The standard’s wording, as the sources below reproduce it:
“Indicates a control material that is intended to verify the performance of another medical device.”
ISO 15223-1:2021, 5.5.2 · ISO 7000-2494
What it means for you
The vial, bottle or swab with this box is not a test and not a sample: it is a material with a known result that you run through the test or meter instead of a real sample, to check that the strips, reagents or meter work and that the test is being done correctly. The everyday example is a glucose meter’s control solution: a drop goes on a strip instead of blood, and the reading must fall inside the range printed on the strip vial. Laboratory analysers run controls at set times for the same reason. If a control reads outside its stated range, results from that kit, strip vial or meter cannot be relied on until the cause is found — the instructions list what to check.
Whether a device is right for you is a question for your pharmacist, nurse or doctor.
- What it looks like
- The word CONTROL in capital letters inside a rectangle, with nothing after it. The same box with a second cell holding a minus or a plus is the negative or the positive control.
- Where you see it
- Glucose-meter and coagulation-meter control solutions, the control vials or swabs inside rapid-test and laboratory kits, and quality-control material for laboratory analysers — on the vial label and next to that item in the kit’s contents list.
- Other names
- CONTROL; control symbol; control material; control solution; ISO 7000-2494
What it does not tell you
It does not give the range the control should read — that is printed on the strip vial, the kit insert or the control’s own leaflet — and it does not say whether the control should give a positive or a negative result; those carry CONTROL − or CONTROL +. It is not a quality-approval mark.
The same box, with a sign
Negative control · ISO 15223-1:2021, 5.5.3. A minus in a cell on the right: a control made to give a negative result, so a positive reading shows the kit or the procedure is at fault. Negative control explained →
Positive control · ISO 15223-1:2021, 5.5.4. A plus in a cell on the right: a control made to give a positive result, so a negative reading shows the test has lost its ability to detect. Positive control explained →
More symbols in “Letters”
Batch code (LOT)ISO 15223-1:2021, 5.1.5
Catalogue number (REF)ISO 15223-1:2021, 5.1.6
Serial number (SN)ISO 15223-1:2021, 5.1.7
Authorised representative (EC REP)ISO 15223-1:2021, 5.1.2
Model number (# in a box)ISO 15223-1:2021, 5.1.10
In vitro diagnostic medical device (IVD)ISO 15223-1:2021, 5.5.1
Negative control (CONTROL −)ISO 15223-1:2021, 5.5.3
Positive control (CONTROL +)ISO 15223-1:2021, 5.5.4
Medical device (MD)ISO 15223-1:2021, 5.7.7
Unique Device Identifier (UDI)ISO 15223-1:2021, 5.7.10
Rx only (prescription device)21 CFR 801.109(b)(1)
Patient number (person with #)ISO 15223-1:2021, 5.7.1Sources
ISO 15223-1 is a paid standard, so the wording above is quoted as 2 publishers’ public documents reproduce it. Each was fetched and read on the date shown:
- NE Scientific: Master Symbol Glossary (CTF-100011 Rev 01) — Shows CONTROL in a box for ISO 15223-1:2021 reference no. 5.5.2: “Control — Indicates a control material that is intended to verify the performance of another medical device”. Checked 2026-10-16.
- QuidelOrtho: QuidelOrtho Symbol Glossary — Shows the same CONTROL box: “Control — Indicates a control material that is intended to verify the performance characteristics of another medical device”, ISO 15223-1:2016 reference no. 5.5.2, ISO 7000:2014 reference no. 2494 (the 2016 edition’s wording). Checked 2026-10-16.
Plain-language parts are in our own words; quotations are the sources’ wording.