Can You Trust an At-Home A1C Test?
Telehealth visits skyrocketed during the pandemic, as did the demand for at-home A1C tests. They are convenient and quick, but how accurate are they? And should they be part of your diabetes management plan post-pandemic?
The COVID-19 pandemic dramatically increased the demand for accurate and reliable at-home A1C tests. Several at-home tests are available that allow users to test from home without having to visit their healthcare provider. However, a recent study suggests that although these tests offer convenience, they don’t always deliver the same accuracy as laboratory A1C tests.
A1C has long been the standard measure to evaluate blood sugar levels over time and inform decisions on how to manage blood sugars moving forward.
A study, published in August in Diabetes Technology and Therapeutics, found that at-home A1C tests were not as accurate as their certifications and approvals might lead people to expect.
In a study of 219 people with type 1 or type 2 diabetes, researchers found large discrepancies in the results of three at-home A1C tests. The Home Access test performed the best, followed by the A1CNow+ test, with the CoreMedica test demonstrating the lowest accuracy.
Although these results are not as good as laboratory A1C tests, at-home A1C tests can still help healthcare providers and people with diabetes, especially during a global pandemic.
“In a time of a pandemic, … being able to get the data from an at-home hemoglobin A1C test has value,” said Dr. Laura Jacobsen, assistant professor and pediatric endocrinologist at the University of Florida and lead researcher on the study.
“For patients, a blood draw is the best, and then the A1C test in your doctor’s office, and at-home are the least accurate,” Jacobsen said. “But the [at-home tests] still have value.”
How A1C tests work
Simply put, A1C tests measure sugar in your blood. Hemoglobin (Hb) is a protein inside red blood cells that transports oxygen through the body and gives blood its red color.
When the blood sugar is high, more sugar binds to hemoglobin and that is reflected in the A1c test. A1c tests are an estimate of the average amount of glucose in the blood.
Red blood cells last about three months before being replaced, which is why A1c tests reflect glycemic control for approximately the past 90 days.
Not all tests are created equal
In order to understand the varying results from the study, it’s helpful to understand various types of A1C tests:
At-home rapid tests. With these tests you can prick your finger at home and add your blood sample to the test tray, insert the tray into the reader, and get results in minutes.
At-home, mail-in tests. The user gets a finger stick blood sample and mails it to a laboratory. Results usually return in a matter of days or weeks.
Office capillary tests. Usually a fingerstick test during a visit to the office or clinic; a small in-office analyzer provides results, usually during the visit.
Venous blood laboratory tests. A blood sample is drawn from a vein for a more sensitive and accurate laboratory analysis.
Typically, testing A1c levels at a medical office or lab will provide more accurate results, but these visits are not an option for everyone.
At-home A1C tests for underserved populations
“If you have a patient out in rural America who doesn’t have access to drive to the endocrinologist every three months, we can mail them a kit,” said Jacobsen. “They can do the A1C at home, and it helps us know if their A1C is 7% or 10%. That really helps us in directing management.”
For many people, at-home tests may be the best, and sometimes only, option. “If we’re talking about a population who’s never been diagnosed, who doesn’t have access to primary care, and we can use the tests just to get a general sense of where someone’s sugars are – there’s huge utility,” said Jasmine Gonzalvo, director of the Center for Health Equity and Innovation at Purdue University.
In other words, some data is much better than no data.
At-home tests provide “a huge opportunity in rural, uninsured, underinsured, immigrant, non-English speaking populations, that may not access the health care system for whatever reason,” said Gonzalvo.
CGM and time in range
Continuous glucose monitors (CGM) are wearable devices that continuously monitor glucose levels, providing immediate, actionable data and showing trends in glucose fluctuations.
The continuous measurements from CGM allow people with diabetes to measure their time in range (TIR), which refers to the percentage of time a person’s blood glucose value stays within their target range (typically 70 to 180 mg/dL). Unlike A1C, time in range provides information about daily fluctuations in glucose levels. However, not all people with diabetes have access to a CGM,
“I prefer time in range,” said Jacobsen. “But the big thing for me is that even though a lot of people have CGM, not everyone has it. We still have a lot of type 1s, especially adults, who can’t get CGM [insurance] coverage and many patients with type 2 still can’t get CGM. So until we can get access improved and the cost down, we still need A1C.”
Gonzalvo agreed that CGM data has become the gold standard in diabetes management.
“CGM will really give you the wealth of information that you really need,” said Gonzalvo. “But when you’re talking about someone doing finger sticks, now we’re talking about needing home A1C tests.”
Examples of at-home A1C tests
At home, immediate results
ReliOn A1C Self Test System
CVS At Home A1C Test Kit
Walgreens At-Home A1C Test Kit
At home, mail to lab, wait for results
Summary of pros and cons of at-home A1C tests
Privacy to avoid stigma associated with less-than-perfect test results
Early detection possibly before symptoms
Can help motivate people to better manage their health
Can be less expensive than lab testing for those with limited or no insurance
Risk of a mistake using the device
Risk of misinterpreting results
May not be covered by insurance
Using home tests in place of visits with a healthcare provider
For more about A1C tests, what their results mean for you, read What's a "Normal" A1C? When is it Misleading?
For more on the value of time in range, a new metric for daily diabetes management, click here.