ISO 15197 Accuracy Standards Evolution

ISO 15197 Accuracy Standards Evolution

ISO 15197 is the international standard for blood glucose meters and strips that people use to test themselves. It has had two editions so far, and the second one asks for noticeably tighter accuracy than the first [2]. A third edition is in the works, but as of October 2026 it isn't published [5].

Key Milestones

• ISO 15197:2003 asked that at least 95% of a system's results land within ±15 mg/dL of a lab reference below 75 mg/dL, and within ±20% at or above 75 mg/dL [2].
• ISO 15197:2013, published in May 2013, moved the cut point to 100 mg/dL: at least 95% of results within ±15 mg/dL below 100 and within ±15% at or above it [2] [4]. It also added a second bar. At least 99% of results must fall in zones A and B of the Consensus Error Grid, a chart that sorts meter errors by how much harm they could cause [2].
• The next edition: ISO now lists the 2013 edition as "to be revised," and a third edition sits at committee-draft stage with no publication date yet [4] [5].

The 2013 edition did more than move the numbers. It added required testing for hematocrit (the share of blood made up of red cells) and for interfering substances such as medications, and it spelled out the lay-user test far more precisely than the 2003 version did [2]. If hematocrit or an interfering substance shifts results by more than 10 mg/dL (or 10% above 100 mg/dL), the manufacturer has to say so in the instructions for use [2].

One thing we wanted to get straight: ISO 15197 is a voluntary standard, not a law. In the European Union it is the standard applied to self-testing meters before they reach the market [2]. The FDA goes further. Here's what surprised us: its over-the-counter guidance says the ISO 15197 criteria "are not sufficient to adequately protect lay-users," and it asks for 95% of results within ±15% and 99% within ±20% across a meter's whole measuring range [1].

Impact on Technology and Manufacturers

The 2013 edition pushed strip makers to show how their systems behave across hematocrit levels and with common interfering substances, because those results now had to be tested and, past the thresholds above, disclosed [2]. Some strip designs correct for hematocrit with extra electrodes and signal processing; we walk through how that works in Hematocrit and Interference Correction.

The move away from older GDH-PQQ strips (glucose dehydrogenase with a pyrroloquinoline quinone cofactor) had a different cause, and it came first. In August 2009, the FDA warned that GDH-PQQ strips can't tell glucose from sugars such as maltose, xylose and galactose, and that these falsely high readings had been linked to 13 deaths reported from 1997 to 2009 [3]. The same notice said glucose oxidase, GDH-NAD and GDH-FAD strips aren't affected by those sugars [3]. FreeStyle Lite strips were on the FDA's 2009 list of GDH-PQQ products, and in May 2010 the FDA cleared FreeStyle Lite strips that use GDH-FAD instead [3] [6].

GDH-PQQ didn't disappear entirely. Roche's Accu-Chek Aviva Plus strips, cleared in 2011, use a modified ("mutant") GDH-PQQ enzyme [7], and Roche still lists them on its US site as of October 2026 [8]. Their FDA decision summary still notes that galactose above 15 mg/dL will push results too high [7]. A 2017 case report also described falsely high readings from maltose on a meter using mutant GDH-PQQ chemistry, so it's worth checking any strip's labeling for its own interference list [9].