OUR PCR TEST
We use a Polymerase Chain Reaction (PCR) technology called Strand Invasion Based Amplification (SIBA)
PCR and SIBA are in principle the same - PCR uses heat to separate the DNA strings while SIBA is using a probe/enzym system (chemical separation of DNA strings)
PCR is characterized by cycling in heat temperature to achieve amplification of the DNA, while SIBAs use
constant temperature (isothermal).
THE BIOCHEMICHAL PROCEDURE IS:
The DNA strings are separated by a probe/enzyme (instead of heating to 94°C).
The process is run at a constant temperature of 44°C (instead of cooling to 72°C).
Every time a doubled stranded DNA string is separated by the probe/enzyme, two synthetic DNA pieces (primers) are attached to each DNA string and by use of the polymerase enzyme the single stranded DNA is made into a double stranded DNA whereby the product is amplified.
This continues for 30 minutes, all the time at a constant temperature of 44°C.
Dependent on the virus load (number of copies) the amplification process starts as early as after 12 minutes and by the 30 minutes it is exhausted and result is reported.
SIBA is documented to detect as low as 2.5 copy of the RNA, while we claim a LoD (Limit of Detection) of 25 copies which is the same as in traditional PCR.
It is the LoD which is important because it tells how secure the test is to find a positive (sensitivity and specificity is also important but does not say how low copy numbers the test can detect – in other words how safe it is).
WHAT IS THE DIFFERENCE BETWEEN TRADITIONAL PCR AND ISOTHERMAL PCR?
Instead of heating up to 95°C and cooling down to 72°C as in traditional PCR, SIBA uses a combined probe/enzyme system to separate the two DNA strings.
The probe is called an invasion probe and the enzyme is called a recombinase, plus SIBA then uses a
polymerase enzyme just like in traditional PCR.