# On Call GK Dual Glucose vs Ketone Testing: Differences, Strips, Sample Size & Results **By Dr Pramod kumar** · 2026-09-26 The **On Call GK Dual** is called a dual monitoring system because one meter can measure both **blood glucose** and **blood β-ketones**. However, glucose and ketone testing are not the same test. They use different strips, different sample requirements, different result times and different measurement ranges. This guide explains the practical differences between **glucose vs ketone testing on the On Call GK Dual**. For the full meter guide: [**On Call GK Dual Complete Guide →**](/blogs/knowledge-hub/on-call-gk-dual-glucose-ketone-monitor-complete-guide) * * * ## Glucose vs Ketone Testing: Quick Comparison Feature Glucose Test Ketone Test Measures Blood glucose Blood β-ketone Compatible strips On Call Chosen / Advanced On Call Blood Ketone Strips Approx. sample **0.8 µL** **1.2 µL** Approx. result time **5 sec** **10 sec** Measurement range 10–600 mg/dL 0–8.0 mmol/L Main display unit mg/dL or mmol/L depending on market mmol/L Code family A = Advanced / H = Chosen Ketone-specific code Same strip? **No** * * * ## What Does the Glucose Test Measure? The glucose test measures the concentration of **glucose in whole blood**. GK Dual supports glucose testing using compatible: - On Call Chosen Blood Glucose Test Strips, or - On Call Advanced Blood Glucose Test Strips. The published sample requirement is approximately **0.8 µL**, and the result appears in approximately **5 seconds**. * * * ## What Does the Ketone Test Measure? The ketone test measures **blood β-ketone (beta-hydroxybutyrate)**. It uses: **On Call Blood Ketone Test Strips.** The published sample requirement is approximately **1.2 µL**, and the result appears in approximately **10 seconds**. [**Shop On Call Blood Ketone Test Strips →**](/products/ketone-monitor-strips) * * * ## Why Does One Meter Need Two Different Strip Types? Glucose and β-ketone are different analytes. Each test strip contains a reagent system designed specifically for the substance being measured. Therefore: - a glucose strip cannot be used to measure ketones, and - a ketone strip cannot be used to measure glucose. The GK Dual meter is shared; the test strips remain test-specific. * * * ## Glucose Sample Size vs Ketone Sample Size The ketone test requires a slightly larger blood sample: - Glucose: approximately **0.8 µL** - Ketone: approximately **1.2 µL** This difference means a blood drop adequate for a glucose test may not necessarily be adequate for a ketone test. * * * ## Glucose Result Time vs Ketone Result Time - Glucose result: approximately **5 seconds** - Ketone result: approximately **10 seconds** Do not assume that the meter has failed simply because the ketone test takes longer than the glucose test. * * * ## Glucose Measurement Range The published GK Dual glucose range is approximately: **10–600 mg/dL** Results outside this range can appear as HI or LO. * * * ## Ketone Measurement Range The published β-ketone range is approximately: **0–8.0 mmol/L** A ketone HI message indicates a result above the meter's reportable range. * * * ## Does GK Dual Use Different Codes for Glucose and Ketones? Yes. For glucose: - **A** = On Call Advanced - **H** = On Call Chosen Ketone strips use their own corresponding code information. Always check that the displayed code matches the strip vial or foil pouch before testing. * * * ## How Does GK Dual Identify a Ketone Test? When a compatible ketone strip is inserted, the display shows the **KET** indicator together with the appropriate ketone code. This helps distinguish ketone mode from glucose mode. * * * ## What Is the “Ketone?” Message During a Glucose Test? The **Ketone?** reminder is not a ketone result. It can appear during a glucose test when the glucose result is above approximately **300 mg/dL**, when the ketone indicator feature is enabled. It is a prompt to consider ketone testing according to the manufacturer's instructions and your healthcare plan. * * * ## When Is Glucose Testing Used? Blood glucose monitoring is used according to the testing schedule recommended for the individual by their healthcare professional. The GK Dual includes: - before-meal markers, - after-meal markers, - glucose averages, - hypo warnings, - hyper warnings, and - test reminders. * * * ## When Is Ketone Testing Used? Blood ketone testing may be included in a diabetes sick-day or emergency plan when advised by a healthcare professional. The meter provides a measurement of blood β-ketones. It does **not independently diagnose diabetic ketoacidosis**. Follow the individual action plan supplied by your healthcare professional. * * * ## Can You Use the Same Blood Drop for Both Tests? Do not assume that one strip or one testing sequence performs both measurements. Glucose and ketone tests are separate procedures using separate strips. Follow the manufacturer's instructions for each test individually. * * * ## Can You Re-Dose the GK Dual Strip? The manufacturer instructions describe a short second-sample opportunity when the first sample is insufficient and the countdown has not started. For ketone testing, the second drop must be applied within approximately **3 seconds** under the specified conditions. Do not add more blood after the normal countdown begins. * * * ## Glucose HI/LO vs Ketone HI Message Test Type Meaning HI Glucose Above approximately 600 mg/dL LO Glucose Below approximately 10 mg/dL HI Ketone Above approximately 8.0 mmol/L Always confirm which type of test is being performed before interpreting the display. * * * ## How to Avoid Mixing Up Glucose and Ketone Strips 1. Read the complete strip product name. 2. Check whether the strip says glucose or blood ketone. 3. Confirm the code type. 4. Check the meter display before adding blood. 5. For ketones, confirm the KET indicator. 6. Never identify strips only by colour or shape. For full compatibility information: [**On Call GK Dual Strip Compatibility Guide →**](/blogs/knowledge-hub/on-call-gk-dual-strip-compatibility-guide) * * * ## Frequently Asked Questions ### Does GK Dual measure both glucose and ketones? Yes, with the correct separate compatible strip for each test. ### Are glucose and ketone strips the same? No. They measure different analytes and are not interchangeable. ### How much blood does glucose testing require? Approximately 0.8 µL. ### How much blood does ketone testing require? Approximately 1.2 µL. ### How fast is the glucose result? Approximately 5 seconds. ### How fast is the ketone result? Approximately 10 seconds. ### What does KET mean? It identifies ketone testing mode. ### What does Ketone? mean? It is a reminder that can appear after a high glucose result; it is not itself a ketone measurement. ### Can ketone strips test glucose? No. ### Can glucose strips test ketones? No. * * * ## Related GK Dual Guides - [GK Dual Complete Guide](/blogs/knowledge-hub/on-call-gk-dual-glucose-ketone-monitor-complete-guide) - [GK Dual Strip Compatibility Guide](/blogs/knowledge-hub/on-call-gk-dual-strip-compatibility-guide) - [GK Dual Error Codes & Troubleshooting](/blogs/knowledge-hub/on-call-gk-dual-error-codes-troubleshooting-guide) - [Ketone Strips Expiry & Storage Guide](/blogs/knowledge-hub/on-call-gk-dual-ketone-strips-expiry-storage-guide) * * * **Medical information notice:** This comparison explains the technical differences between glucose and ketone testing on the GK Dual. It does not determine when an individual should test, interpret whether a result is medically safe or diagnose diabetic ketoacidosis. Follow your healthcare professional's testing and action plan. --- > Source: [Microsidd India](https://microsidd.com/blogs/knowledge-hub/on-call-gk-dual-glucose-vs-ketone-testing-guide)