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Ketone Reading Guide

Blood, breath, and urine tests measure different ketones on different scales. This guide identifies the measurement you entered and applies conservative blood and urine safety routes. It does not diagnose a medical condition or label a reading as a weight-loss, wellness, or therapeutic target.

If a clinician has given you a diabetes or ketone sick-day plan, follow that plan instead of this guide.

Adult scope: This guide is for adults. For a child or teenager, use the pediatric diabetes or ketone plan from their care team. Seek emergency help for the warning symptoms below.

When not to use an online interpreter

Get emergency help now for repeated vomiting or inability to keep fluids down, abdominal pain while very unwell, rapid or deep breathing, confusion, or unusual sleepiness. Do not wait for glucose to become high: DKA can occur with lower glucose, particularly with SGLT2-inhibitor use and during pregnancy.

A home glucose or ketone result cannot diagnose or exclude DKA because it does not measure blood pH or bicarbonate.

What each test measures

TestMeasurementImportant limit
Blood meterCirculating beta-hydroxybutyrate (BHB)A home BHB value does not measure acidosis or establish a nutrition target.
Breath meterBreath acetoneDevice scales vary and do not have a reliable one-to-one BHB conversion.
Urine stripExcreted acetoacetateTiming, hydration, and the product color scale affect the result. A moderate or large category with diabetes, SGLT2-inhibitor use, or pregnancy routes to urgent medical guidance.

Check a ketone reading

Supported input: 0–20 mmol/L.
Safety context

Select every statement that applies right now.

Safety check and reading

No result yet. Enter a reading, complete the safety context, and select “Check this reading.”

What the DKA criteria actually require

The 2024 ADA/EASD/JBDS/AACE/DTS consensus requires all three parts for a DKA diagnosis: diabetes or glucose at or above 200 mg/dL (11.1 mmol/L), ketonemia (blood BHB at or above 3.0 mmol/L or urine ketones at 2+ or higher), and metabolic acidosis. A home meter cannot assess the acid-base criterion.

The same consensus recognizes euglycemic DKA, so normal or lower glucose cannot rule it out. SGLT2 inhibitors, pregnancy, and reduced food intake are among contexts in which a lower-glucose presentation may occur. See the 2024 hyperglycemic-crises consensus report.

How this differs from GKI

GKI is a glucose-to-BHB ratio proposed for research monitoring; it is not a DKA screen. If you have blood readings taken at roughly the same time, the GKI calculator checks both raw values before doing the arithmetic. Its methodology is described in the original 2015 GKI paper.

  • GKI Calculator

    Calculate a research ratio only after raw glucose and blood-BHB safety checks.

  • What are ketones?

    Learn what blood, breath, and urine measurements represent.

  • Signs of ketosis

    Separate common observations from unsafe diagnostic shortcuts.

Frequently asked questions

Does a lower or normal glucose value rule out DKA?
No. The 2024 international consensus recognizes euglycemic DKA, including presentations associated with SGLT2 inhibitors and pregnancy. A home tool also cannot measure the metabolic acidosis required for diagnosis, so glucose and ketone readings cannot diagnose or exclude DKA on their own.
What should I do with blood BHB at or above 3.0 mmol/L?
Get urgent medical advice rather than treating it as a nutritional-ketosis target. If you also have diabetes, take an SGLT2 inhibitor, are pregnant, have glucose at or above 200 mg/dL, or have concerning symptoms, seek emergency assessment. A clinician must check acid-base status to determine whether DKA is present.
Can breath or urine ketones be converted to blood BHB?
Not reliably. Breath devices use manufacturer-specific acetone scales, and urine strips measure excreted acetoacetate rather than circulating BHB. Use the product instructions and do not use an indirect result to rule out DKA.
Does this guide provide a target for weight loss?
No. A ketone number is not a validated weight-loss or wellness score. This guide reports the measurement type and applies a safety check; it does not recommend chasing a higher reading.
Can I use this guide for a child or teenager?
No. The safety routes on this page are scoped to adults and cite an adult hyperglycemic-crises consensus. Use the pediatric diabetes or ketone plan supplied by the child's care team, and seek emergency help for warning symptoms.