GreenLight for SARS-CoV-2 antibody measurement

While SARS-CoV-2 antigen testing remains vital, those who have recovered or been vaccinated may now want to know their antibody level. ams OSRAM’s spectral sensor can now guide answers.

The current controversy is who, where and when to give booster vaccinations? 

When the body senses invading viruses, antibodies are called out to fight them. In both cases – vaccine-induced immunity and natural infection – antibodies against the virus are generated. However, their number can decline over time, and with it the level of protection. A new Digital Rapid Test based on ams OSRAM’s proven spectral sensor can now be used to determine the level of antibodies a person has developed against SARS-CoV-2. In fact, the principle is the same as with the COVID-19 antigen test, just with a different biochemical substance composition on the test strip.

The spectral sensor is essential to achieve the possibility of high quality, decentralized testing as part of a proprietary, cloud connected solution ams OSRAM provides the PCB with sensors, light sources, optical module, and wireless connection. A design-in guide makes it easy for manufacturers to integrate the PCB in their innovative products.

Upon applying a small blood sample, the biochemistry leads to a colorization of the strip´s test and control line. The spectral sensor measures the corresponding color change.

Two LEDs shine sequentially on the test line and control line position: A proportion of the emitted light is absorbed and the spectrum of the reflected signal is measured.

The degree of discoloration of the line is directly proportional to the antibody amount (i.e. the level of antibodies in a blood sample). The more antibodies, the higher the color intensity.

And even though there is still debate in the scientific community, there is a reference between the amount of antibodies and the need for revaccination – the so-called booster.

In fact, the World Health Organization defined a standard to determine the number of antibodies in blood: BAU/ml (binding antibody units per ml). The latest findings show that below 50BAU/ml revaccination is strongly recommended; between 50 and 150BAU/ml, revaccination is recommended; and above 150BAU/ml, revaccination may not be immediately necessary.

Tests to determine the antibody amount are currently performed in laboratories or with Point of Care Testing (POCT) at pharmacies or at the general practitioner. However, standard Lateral Flow Test cannot objectively and reliably quantify the titer. Some solutions use ‘scorecards’ to compare line-color intensity, but these can be prone to user error. An alternative to quantify the result are benchtop readers, but the corresponding equipment is expensive, bulky and needs regular maintenance.

In comparison, the Senova GreenLight platform can now provide semi-quantitative results, distinguishing between antibody levels: <150 BAU/ml between 150 BAU/ml and 1000 BAU/ml or >1000 BAU/ml. This is also in a single use device with all electronics integrated in the test cassette. The results are much more objective and reliable than with scorecards and from a treatment point of view the result is equivalent to the currently-performed, more expensive, and more time-consuming lab tests.

In addition, GreenLight provides these objective and reliable results in around 15 minutes, so the patient can get the vaccination directly after the check, if necessary. No follow-up at the doctor´s office is needed.

Also for the individual, it may be useful to know the antibody level before deciding for a booster vaccination or if the vaccines gave the person the expected immunity protection. With this test, you can quickly determine ‘on the spot’ if you need a booster vaccination now or if someone else can receive this resource. To measure antibody level, no other Point of Care (POC) sensor platform has such high sensitivity, delivering a quantification, and enabling multi-analyte measurement.

The results are immediately available, digitized in a certified medical cloud.


A quick Point of Care Test to measure antibodies for several important diseases

LFTs are already widely used in point-of-care applications. The advantages are obvious: their ease of use allows on-site testing, they deliver results within a few minutes, and their design is simple and cost effective. On top of that, a digital output allows for a Bluetooth Low-Energy (BLE) connection to mobile devices and medical-approved cloud services.

Most important value added by the ams OSRAM sensor platform includes high sensitivity, quantification, and multi-analyte measurement.

Currently, the GreenLight test is a disposable solution, but in near future the reader will be reusable.

SARS-CoV-2 antigen and antibodies are only two important applications of the technology. Depending on the included and replaceable strip, there will be ‘GreenLight’ for the measurement of pathogens such as bacteria, cardiovascular markers like troponin, proteins, hormones, vitamins and many more.

More information about our spectral sensor technology