Hemoglobin a1c testing

Types of Hemoglobin A1C Testing

When it comes to hemoglobin A1c testing, there are several methods available. Health practitioners select the best method depending on the patient’s health status and needs, lab equipment, and resource availability.

Here are some of the main types of hemoglobin A1c testing:

• High-Performance Liquid Chromatography (HPLC)

  This is arguably the most popular and reliable method for measuring hemoglobin A1c. Hemoglobin A1c test kits often employ HPLC in clinical laboratories for its accuracy and ability to separate different hemoglobin types. HPLC identifies and quantifies the proportion of glycated hemoglobin to total hemoglobin. This gives a clear percentage of A1c. It is also worth mentioning that this method is often used to calibrate other systems due to its precision.

• Immunoassay

  This method utilizes antibodies to attach the form of hemoglobin that is glycated. After this binding, the unbound hemoglobin is washed off. Then, the complex (bound hemoglobin with antibodies) is detected through a labeled secondary antibody. This method is popular for its convenience. After all, immunoassays can be automated, enhancing the ease of testing.

• Capillary Electrophoresis

  Capillary electrophoresis is gaining ground as a method for hemoglobin A1c testing due to its ability to resolve different hemoglobin variants. It is a quick and precise method that separates glycosylated and non-glycosylated hemoglobin based on their charges and moves them through a charged capillary. The result is usually ready within minutes. This, alongside the ability to test for variants, makes this method appealing to many practitioners.

• Agarose Gel Electrophoresis

  Agarose gel electrophoresis offers a more traditional approach to A1c testing. It involves separating different hemoglobin types by their charges in an agarose gel matrix. While less frequently used than other methods like HPLC, it is valuable in clinical settings where hemoglobin variants might interfere with other tests. It is also a time-consuming method compared to HPLC and other test kit methods, limiting its use in the commercial market.

• Ion Exchange Chromatography

  Ion exchange chromatography is another method for hemoglobin A1c testing. It is similar to HPLC, but it uses an ion exchange resin instead of a chromatography column. This method is very precise and is often used in reference laboratories to ensure effective and accurate results.

Features of Hemoglobin A1C Testing

Hemoglobin A1c testing comes with many salient features. Here’s a list:

• Glycemic Control Assessment

  Diabetes blood test primarily assesses an individual’s average blood glucose levels over the past two to three months. This gives a better picture than just assessing blood sugar levels at one point in time. Because of this ability, A1c tests are invaluable in managing diabetes. In fact, they help healthcare providers adjust treatment plans to ensure the patient’s blood sugar levels stay within the target range.

• Laboratory and Point-of-Care Testing

  Hemoglobin A1c tests can be performed in the laboratory and by point-of-care equipment. The patients always visit the lab or clinic for the test, but it can also be done during a routine medical appointment using a portable device. This portable device is under the care of a healthcare professional. Conducting the test in the lab allows for more sophisticated testing methods. Conversely, the A1c test done via portable devices during checkups is often more convenient for quick assessments.

• Testing Frequency

  How often a patient does an A1c test is determined by their health status and whether diabetes is controlled or not. Patients with uncontrolled diabetes, for instance, are likely to get frequent testing so that there is adequate information on how the disease is being managed. However, stable patients may only need to do it twice or thrice a year.

• Comparison with Fasting Glucose Tests

  An advantage of the A1c test is that it does not require fasting. This is unlike plasma glucose tests, which require fasting and often take a few hours. This non-fasting feature makes the A1c test simpler and more flexible for both patients and healthcare providers. Blood level fluctuations do not affect the A1c test as they do the glucose test, making it a more stable and reliable measure of long-term glucose levels.

How to Use Hemoglobin A1C Testing

It is important to note that A1c testing kit uses differ slightly depending on whether health practitioners are using laboratory tools or portable devices for their A1c testing. This is because laboratory tools often involve complex procedures compared to portable devices that can be more straightforward in clinical or field settings.

That said, there are still general preparation and procedure guidelines regardless of the device used for the test.

Preparation

• No Fasting Requirement: The good thing about the A1c test is that there is no need for the patient to fast before taking it. This is unlike glucose tests requiring fasting. However, fasting helps get more accurate results.
• Regular Monitoring: Patients undergoing regular monitoring of their diabetes conditions should schedule their A1c tests according to their healthcare provider’s recommendations. The recency of the test helps in effective management of the disease.
• Sample Collection: For the A1c test performed in the laboratory, healthcare professionals collect blood samples from the patient’s vein using a sterile needle. Conversely, during the test using portable devices, the healthcare professional may collect drops of blood from the patient’s fingertip. They collect the drops using a small pricking device that punctures the fingertip.
• Device Setup: A key difference between the test in labs and the one using portable devices is that health practitioners have to set the device properly, especially during the first few uses of the device. They have to calibrate it so it gives accurate results. They must also insert the test strips and ensure they are properly set for efficient data collection.
• Test Strip Preparation: Some portable devices require users to prepare the test strips by applying the drop of blood onto the strip. It is vital to ensure that the blood drop is wide enough to cover the entire strip so the strip absorbs the blood properly. The results will be inaccurate if the blood drop is too small or too big.

Steps

• Blood Sample Collection: Blood samples are collected from a vein or fingertip, as already mentioned earlier.
• Saline Solution Preparation: Saline solution is prepared after collecting the blood samples. It is using carefully controlled conditions to ensure the hemoglobin is stable and undamaged.
• Measurement Process: After the blood sample preparation, the amount of glycosylated hemoglobin in the blood is measured using high-performance liquid chromatography. Hemoglobin moves through a chromatography column where it interacts with a glucose-laden surface. The hemoglobin that is not glycated is washed off hemoglobin, leaving behind glycated hemoglobin. The glycated hemoglobin is then eluted and separated from the non-glycosylated form. Hemoglobin A1c is quantified by measuring the amount of light that reflects off the hemoglobin. Hemoglobin A1c that is glycated takes up more light than the non-glycosylated form.

How to Maintain Hemoglobin A1C Testing

Maintaining hemoglobin A1c testing apparatus and supplies is critical for effectiveness and for getting accurate results. Here’s a comprehensive guide on maintaining these kits:

• Device Maintenance

  Devices used for A1c testing, especially the portable ones, require regular checks. These checks ensure they are functioning properly. The first thing one should do is follow the manufacturer’s recommendations on how to clean and maintain the device. Some manufacturers may advise doing certain checks after a specific period. One should also follow the guidelines to ensure the device serves its purpose effectively. Also, healthcare professionals should frequently calibrate A1c testers to guarantee the devices give accurate results.

• Test Strips Storage:

  For the A1c tests done using portable devices, the condition of the test strips plays a pivotal role in determining whether the results are accurate or not. Therefore, to ensure the strips work well, keep them in a cool, dry place. One should avoid using them after their expiration date. Using A1c test strips beyond their expiry date will yield inaccurate results. Additionally, always close the container immediately after taking out one of the strips to avoid moisture affecting the remaining strips.

• HPLC Systems Maintenance and Appointments

  On the other hand, maintenance of the machine used for hemoglobin A1c testing kits, such as HPLC machines, requires additional care. These machines are fairly complicated. Hence, it is usually advised that they are maintained and repaired by qualified technicians. These technicians follow the manufacturer’s guidance to ensure the machine functions effectively. Also, like any other machine, HPLC requires regular servicing. The maintenance schedules are usually based on the volume of tests performed. There are also occasions like during peak periods when the servicing should be done more frequently to prevent the machine from breaking down.

• Environmental Conditions

  The effectiveness of the equipment and supplies used during hemoglobin A1c testing is largely dependent on environmental conditions. Therefore, to ensure the equipment always works properly, one must keep the machines and devices in a controlled environment. This means that the rooms where these devices are kept should have stable temperatures and not experience sudden extreme heat or cold. While the machines used for A1c test kits are robust, exposure to extreme environmental conditions significantly interferes with their functioning. That also applies to the efficiency of the reagents and controls.

• Reagents Storage:

  The testing kit’s components that come with reagents also require proper maintenance. Healthcare providers should always store the reagents in appropriate temperature conditions as indicated by the manufacturer. One should avoid exposing the reagents to direct sunlight. Doing this damages the reagents and reduces their effectiveness.

• Regularly Monitoring Reagent Expiration Dates

  One should always use fresh reagents. People should always check the expiration dates of the reagents before using them. The results of hemoglobin A1c tests may be inaccurate if providers use reagents that have expired. This even applies to consumables like pipettes and cuvettes. It is advisable to replace any item that a provider uses repeatedly and that undergoes wear and tear.

Q&A

Q. What is a normal hemoglobin A1C level for a healthy person?

A1C levels of below 5.7 % are considered normal. This means the individual has normal blood glucose levels over the past two to three months.

Q. What is the difference between Hemoglobin and Hemoglobin A1C?

The essential difference between hemoglobin and hemoglobin A1c is that while hemoglobin refers to the protein in red blood cells that carries oxygen throughout the body, hemoglobin A1c refers to the portion of that protein that is glycated how much glucose has interacted with hemoglobin.

Q. Is hemoglobin A1C test chemistry or hematology?

It is neither chemistry nor hematology. It is a branch that combines the two and studies the hemoglobin forms to which glucose has bound. This branch also studies the mechanisms behind that binding.

Q. How accurate are the A1C home tests?

While A1C home tests are accurate, they may not be as precise as laboratory tests. According to the ADA, home A1C test kits should yield results that are within 0.5%-1% of the accurate value. Some factors that may cause hemoglobin A1c test results discrepancies include hemoglobin variants and conditions that affect red blood cell life spans, such as anemia.