Did you know hemoglobinopathies like Sickle Cell Anemia and Trait can affect the Hgb A1c reading? African Americans have an increased risk of inheriting sickle cell trait. In fact, about one in 12 African Americans has the sickle cell trait. This is important because about 12.7 African Americans ages 18 years or older have diabetes, therefore, many will have both diabetes and sickle cell trait.

Why is this important to the NURSE PRACTITIONER?

Depending on the lab method used, A1c tests in patients with hemoglobinopathies result in falsely high or low results. For the sickle cell trait, you will typically see a low result. Because of this, healthcare providers may falsely underdiagnose or undertreat diabetes. The A1c test can be unreliable for diagnosing or monitoring diabetes and prediabetes with hemoglobinopathies.

What should the NURSE PRACTITIONER do?

Start by identifying the hemoglobinopathy and you should suspect something is not right when:

An A1c result is different than expected
An A1c result is above 15%
Results of self-monitoring of blood glucose have a low correlation with A1c results
A Patient’s A1c result is radically different from a previous A1c result following a change in laboratory A1c methods

When the A1c test is used for diagnosis, the blood sample must be sent to a laboratory that uses an NGSP-certified method for analysis to ensure the results are standardized. Also, healthcare providers should not use the A1c test for patients with a disease condition such as HbSS, HbCC, or HbSC.

Alternate Test Option?

There are reliable A1c tests available that do not cause interference with hemoglobin variants. Also, a provider can diagnose diabetes without using the Hgb A1c test. According to the 2021 Standards of Care, diabetes is diagnosed with:

Fasting plasma glucose >126 mg/dL
2hr OGTT >200 mg/dL

This needs to be confirmed with a second test without delay (can be the same test or a different one) unless the patient exhibits classic symptoms then a random plasma glucose >200 mg/dL will suffice. If you need to monitor a person with diabetes and the Hgb A1c test is not an option, you could use the Fructosamine test, also called glycated serum protein or glycated albumin. This test is similar to the A1c but shorter time period. The test shows average glucose levels over a much shorter period of time than the A1c test, usually about 2-3 weeks. Please note that the Fructosamine test is not standardized and the relationship of results of them test to glucose levels or risk for complications has not been established.

To learn more about this topic, I’ll link a good article >HERE< for your reading please. The above topic, I covered on my Instagram called TUESDAY TIPS. I go LIVE on my Instagram to answer or address common issues or questions with diabetes management. If you would like to catch them LIVE, make sure you follow me over on Instagram >HERE<. Also, I've made a YouTube playlist if you want to catch the past ones. You watch them >HERE<. I would love for you to check it out and while you are there, please SUBSCRIBE to my YouTube channel, Kim E. The Diabetes NP. I put out weekly videos with the nurse practitioner in mind! Lastly, have a GREAT WEEK !