The following methods and technologies are used to measure and monitor blood glucose levels:
- Classic laboratory method
- Glucometer
- Band-Pass Raman Spectroscopy for Glucose Measurement
- Continuous Glucose Monitoring (CGM) System
Classic laboratory method
This method measures glucose from a blood sample taken from a vein or finger. Blood is in a test tube for further analysis. Taking a blood sample from venous plasma allows measurement of the following: random glycemia, fasting glycemia, OGTT (oral glucose tolerance test), and HbA1c (value of average glycemia for 2-3 months).
The accuracy of this method is extremely high, which is why it is effective to determine diabetes or insulin resistance through OGTT analysis.
This method is not always reliable for a single fasting blood sample collection. The reason is that the value may differ the next time or depend on many factors (diet, sleep, physical activity).
Glucometer
The glucometer measurement method takes a sample from capillary blood (finger). The glucometer contains a test strip with an enzyme. A test strip is put in the device, which measures an electrical signal proportional to the glucose concentration.
People with diabetes most often use the glucometer. They use it for the purpose of continuous monitoring of glucose levels before the administration of insulin therapy. It is also the cheapest method of monitoring glucose levels. It is good for checking the symptoms of hypoglycemia or hyperglycemia. The results take a few seconds.
Some people avoid using a glucometer because taking a blood sample can be unpleasant, the strips have a limited shelf life, and the method provides only a single glucose reading. However, people who wear a continuous glucose monitor use a glucometer as an additional check in certain situations.
Although glucometers provide only single readings, they are still useful for confirming symptoms of hypoglycemia or hyperglycemia. Post-meal changes are discussed in How Diet Affects Blood Glucose Levels.
Band-Pass Raman Spectroscopy for Glucose Measurement
A new technology in development is measuring glucose using Raman spectroscopy. Raman spectroscopy enables the measurement of glucose by analyzing how glucose molecules change the laser light passing through the sample.
The physical form of this prototype is a smaller device that uses near-infrared light that is directed at the skin at a specific angle. There is no need for pricking and regular blood sampling.
This device does not look only for the glucose levels. It uses a water signal in cases of dehydration and a glucose signal for determining the values.
Although fluidity is not measured directly, the method uses reference Raman signals of water and tissue to correct the measurement and reduce errors caused by dehydration.
Continuous Glucose Monitoring (CGM) System
A system for continuous glucose monitoring (CGM) is one of the most modern solutions for people with diabetes or those who want to monitor their health. CGM measures the level of glucose in the interstitial (intercellular) fluid via an under-the-skin sensor.
The sensor measures the value every 1-5 minutes. In that way, it is possible to monitor the trend of the glucose rise and fall during the day.
Types of CGM Systems
There are several types of CGM systems, but the most accessible and popular are:
- RtCGM, with which glucose levels can be monitored continuously for 15 days. RtCGM (real-time) has a constant transmission of glucose data and the possibility of alarming in cases of hypoglycemia and hyperglycemia.
- isCGM / “flash” CGM, where the value is available by scanning the sensor (NFC) with the phone. Newer generations also have the option of setting an alarm.
- There are also implantable CGMs where the sensor is surgically placed under the skin for several months, while the external transmitter is above. Implantable CGM does not require frequent changes, but it is more complicated to install. For those reasons, the trend of using rtCGM sensors is reasonable.
👉 Next: What Is a Continuous Glucose Monitor (CGM) and How Does It Work?
The goal of this personal glucose monitoring experiment is to understand long-term trends rather than single values. For a complete overview, visit the CGM data–based educational series.
