OneTouch HI Reading — What It Means

What Does This Error Mean?

HI means your blood glucose is above 600 mg/dL (33.3 mmol/L) — higher than the meter can measure. This is a serious medical situation. Do not dismiss this as a meter error. Seek medical attention immediately if you have symptoms such as extreme thirst, confusion, rapid breathing, or fruity-smelling breath.

Affected Models

OneTouch Verio
OneTouch Verio Flex
OneTouch Verio Reflect
OneTouch Ultra 2
OneTouch Select Plus

How to Fix It

Do not assume it is a meter error — act immediately

HI is not a malfunction. It means blood glucose is critically high. If you feel unwell, confused, extremely thirsty, are breathing rapidly, or notice fruity-smelling breath, call emergency services or go to the nearest emergency room immediately.
Retest with a new strip to confirm

If you feel completely normal and have no symptoms, retest once with a new strip to rule out a strip contamination issue (for example, if your finger had residue from sweet food or drink). Wash hands thoroughly with soap and water, dry completely, and retest.
Contact your doctor or diabetes care team

Even without acute symptoms, a confirmed HI reading requires urgent medical contact. Do not adjust insulin or medication doses on your own in response to a HI reading without medical guidance.
Check for strip contamination as a last resort

Fruit juice, jam, honey, or any sugar residue on the fingertip can temporarily cause an extremely elevated false reading. If you retest after thorough handwashing and the reading is now in range, contamination was the likely cause. Still inform your doctor.

Frequently Asked Questions

What does HI mean in mmol/L?

HI means the reading is above the meter's upper measurement limit. For most OneTouch meters, this means blood glucose is above 33.3 mmol/L (600 mg/dL). This is dangerously high and requires immediate medical attention if confirmed.

Can a faulty strip cause a HI reading?

Rarely, but possible — particularly if the fingertip was contaminated with a sugary substance. Always wash hands and retest once before concluding the result is accurate. However, if HI appears on a second clean test, treat it as a real reading and seek medical care.