What That High or Low Lab Result Really Mean

You open your patient portal and notice a red letter beside one of your results:

H for high. L for low.

It is easy to panic. It is also easy to ignore the result if no one contacts you.

Neither response gives you the understanding you need.

A Flag Is Not a Diagnosis

The reference range on your report usually represents a range of results found within a particular group of people.

Ranges can vary based on the laboratory, testing method and population.

A result slightly outside the range does not automatically mean that you have a disease. Your healthcare professional may need to consider your symptoms, medical history, medications and previous results.

Think of the flag as a tap on the shoulder. It says, “Take a closer look,” not necessarily, “Something is terribly wrong.”

Other Factors Can Affect Your Results

Laboratory values may be influenced by:

• Fasting or recent meals

• Hydration

• Recent illness

• Exercise

• Medications and supplements

• Menstruation or pregnancy

• The timing or handling of the sample

For example, an A1C test estimates average blood sugar over approximately three months, but certain anemias, kidney disease, liver disease, blood disorders, pregnancy, blood loss and transfusions can affect its accuracy.

Kidney-function measurements can also be influenced by hydration, illness, medications and muscle mass.

Your healthcare professional may need to look at the trend or repeat a test before reaching a conclusion.

Five Questions to Ask

1. Is this result significantly abnormal?

2. Has it changed from my previous result?

3. Could anything temporary have affected it?

4. Does it need to be repeated or confirmed?

5. What should I do next?

Your takeaway: A laboratory flag requires attention and context—not panic, shame or an automatic diagnosis.

Download the Doctor Visit Cheat Sheet to organize your results, medications and questions before your next appointment.

Empowered health wins.

Sources

MedlinePlus: How to Understand Your Lab Results
https://medlineplus.gov/lab-tests/how-to-understand-your-lab-results/

Centers for Disease Control and Prevention: A1C Test for Diabetes and Prediabetes
https://www.cdc.gov/diabetes/diabetes-testing/prediabetes-a1c-test.html

Medical Disclaimer: This article provides general health education and is not a substitute for individualized medical advice, diagnosis or treatment. Discuss abnormal results with a qualified healthcare professional before changing your treatment.

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