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Error Codes & Troubleshooting

Meter Support

Error Codes & Troubleshooting

Seeing a code on your BKT meter?
Click your error code below to get the fix.

Error Messages

What Does My Meter's Error Code Mean?

Each error code is shown below with what's causing it and what to do. Listed in the order they appear in the owner's manual.

E-b
Battery Too Low
The battery power is insufficient to perform a test
What's happening

The batteries have dropped below the voltage needed to run a test. The meter locks out testing to prevent a result affected by low power. This can happen gradually — you may see the low battery icon appear first before E-b, giving you a warning window to change batteries before testing is blocked entirely.

How to fix it
  1. Turn the meter off and open the battery cover on the back by pressing the edge and lifting it up.
  2. Remove both old batteries and replace with two fresh 1.5V AAA alkaline batteries.
  3. Close the cover — you'll hear a confirmation beep if inserted correctly.
  4. Re-insert a test strip to restart the meter and proceed with your test.
Replacing the batteries does not erase your stored test results. Your history is preserved in memory.
E-2
Expired Strip or Code Chip
The test strip or calibration code chip is past its expiry date
What's happening

The meter detected that the test strip or β-ketone code chip is expired. Expired strips can produce inaccurate readings, so the meter stops the test before a bad result is recorded. This error can also appear if the date set on your meter is incorrect — for example, if the clock reset after a battery change.

How to fix it
  1. Check the expiry date printed on the side of your test strip vial.
  2. If expired, open a new vial of Best Ketone Test strips.
  3. For β-ketone strips, insert the new code chip that came with the new vial to recalibrate the meter before testing.
  4. Check that the date and time on your meter are correct — if wrong, press S with no strip inserted to enter settings and correct them.
  5. Retry your test with a fresh strip from the new vial.
Once a vial is opened, strips should be discarded after 6 months even if the printed expiry date hasn't passed. Write the opening date on the vial label when you first open it.
E-V
Used Test Strip
A previously used strip was inserted into the meter
What's happening

The meter recognized that this test strip has already been used. Each strip can only be used once — reusing one will not produce a valid result. The meter detects this automatically and blocks the test.

How to fix it
  1. Push the strip ejector button on the side of the meter to remove the used strip.
  2. Dispose of it carefully — used strips and lancets are biohazardous. Follow your local disposal regulations.
  3. Insert a brand new test strip from a properly stored, in-date vial.
E-t
Temperature Out of Range
The meter or strips are too hot or too cold to test accurately
What's happening

The meter's operating range is 50°F – 104°F (10°C – 40°C). Testing outside this range produces unreliable readings, so the meter won't allow it. Common triggers include testing in a cold car, near a heat source, or after the meter or strips have been left in an extreme environment.

How to fix it
  1. Move to a room-temperature environment — ideally 68°F–77°F (20°C–25°C).
  2. Allow both the meter and the test strip vial to acclimate for at least 10–15 minutes before retesting.
  3. Retry with a new test strip once both are within the operating temperature range.
E-F
Strip Removed Early or Insufficient Blood
Strip pulled out during countdown, or not enough blood was applied
What's happening

Either the confirmation window on the strip wasn't fully filled with blood before the countdown started, or the strip was removed from the meter before counting finished. Both mean the meter couldn't complete the measurement. This is one of the most common errors and is easily resolved with a fresh strip and a larger blood drop.

How to fix it
  1. Discard the used strip — never try to add more blood to a strip already in use or already counting down.
  2. Insert a new strip and wait for the flashing blood drop icon to appear on screen before applying blood.
  3. Rub your fingertip for about 20 seconds to improve blood flow before lancing.
  4. After lancing, wipe away the first drop with a clean cotton swab, then gently squeeze to get a second drop at least 1.0 µL in size.
  5. Touch the absorbent hole of the strip to the blood drop at a slight angle and hold steady until the confirmation window is completely filled.
  6. Wait for the beep before removing your finger — the meter will count down automatically once blood is detected.
If you don't apply blood within 3 minutes of inserting the strip, the meter shuts off automatically. Remove and reinsert a new strip to start fresh.
E-0
Meter Malfunction
An internal error was detected in the meter
What's happening

This code signals an internal problem with the meter itself — not your strips, blood sample, or testing technique. It is not related to anything you did during the test.

How to fix it
  1. Remove and discard the test strip.
  2. Insert a brand new strip and try the test again.
  3. If the error appears again, contact BKT Customer Support.
E-A
Meter Malfunction
An internal error was detected in the meter
What's happening

This code signals an internal problem with the meter itself — not your strips, blood sample, or testing technique. It is not related to anything you did during the test.

How to fix it
  1. Remove and discard the test strip.
  2. Insert a brand new strip and try the test again.
  3. If the error appears again, contact BKT Customer Support.
E-E
Meter Malfunction
An internal error was detected in the meter
What's happening

This code signals an internal problem with the meter itself — not your strips, blood sample, or testing technique. It is not related to anything you did during the test.

How to fix it
  1. Remove and discard the test strip.
  2. Insert a brand new strip and try the test again.
  3. If the error appears again, contact BKT Customer Support.
E-C
Meter Malfunction
An internal error was detected in the meter
What's happening

This code signals an internal problem with the meter itself — not your strips, blood sample, or testing technique. It is not related to anything you did during the test.

How to fix it
  1. Remove and discard the test strip.
  2. Insert a brand new strip and try the test again.
  3. If the error appears again, contact BKT Customer Support.

Need more help?

If an error persists after following these steps, contact BKT Customer Support.

(833) 977-2378 care@bestketonetest.com
General Troubleshooting

No Error Code, But Something's Wrong?

Common issues and steps from the owner's manual.

Meter shows nothing after inserting a test strip

Possible Cause What to Do
Batteries exhausted Replace the batteries.
Test strip inserted upside down or incompletely Insert the test strip with contact bars end first and facing up.
Defective meter or test strips Contact BKT Customer Support.

Test does not start after applying the sample

Possible Cause What to Do
Insufficient blood sample Repeat the test using a new test strip with a larger volume of blood sample.
Defective test strip Repeat the test with a new test strip.
Sample applied after automatic switch-off (3 minutes after last user action) Repeat the test with a new test strip. Apply sample only when the flashing blood drop symbol appears on the display.
Defective meter Contact BKT Customer Support.

Control solution test result is out of range

Possible Cause What to Do
Error in performing the test Read instructions thoroughly and repeat the test again.
Control solution vial was poorly shaken Shake the control solution vigorously and repeat the test again.
Expired or contaminated control solution Check the expiry date of the control solution.
Control solution too warm or too cold Control solution, meter, and test strips should all be at room temperature 20°C to 25°C (68°F to 77°F) before testing.
Defective test strip Repeat the test with a new test strip.
Meter malfunction or improper working of meter and test strip Contact BKT Customer Support.
Common Questions

Frequently Asked Questions

Will replacing my batteries erase my test history?

No. The manual confirms that replacing the batteries does not affect the test results stored in memory.

Do I need to recalibrate the meter every time I open a new vial of β-ketone strips?

Yes. Each vial of β-ketone strips comes with a code chip. You must insert the code chip before using the new vial to ensure the meter is calibrated correctly. Glucose strips do not require this step.

How long can I keep a vial of strips once opened?

Discard remaining glucose or β-ketone test strips after 6 months from the date you first opened the vial, even if the printed expiry date hasn't passed. Write the opening date on the vial label.

My results seem off but there's no error code. What should I do?

Run a control solution test first. This verifies whether the meter and strips are working correctly together. If the control result falls within the range printed on the strip vial, the meter is functioning properly. If it falls outside range, contact BKT Customer Support before testing again.

How often should I run a control solution test?

The manual recommends running a control solution test when you first receive the meter, at least once a week for routine checks, whenever you open a new vial of strips, if you suspect the meter or strips aren't working properly, if your results don't match how you feel, or if you've dropped or damaged the meter.

What type of batteries does the BKT meter use?

Two 1.5V AAA alkaline batteries. The meter comes with batteries included.

Support

Error Codes

Meter Support Error Codes & Troubleshooting Seeing a code on your BKT meter?Click your error code below to get the fix. ...

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