CT value 40 in RTPCR : a Perspective

Here is a question for you.

Q. How big was the 7 feet tall and 150 kilo hulk of the Great Khali when he started his life’s journey inside his mother’s womb ?

A. O.1 mm to be precise.

That is right.

Every human being starts his life’s journey as a single cell of the size of one tenth of a milimeter inside her mother’s womb. Then one of the strangest things happens. That single cell divides equally into two cells. Each cell shares the same 46 number of gene molecules called chromosome, which implies that before division the chromosomes are duplicated and split into two equal numbers.

By the 40th cell division that one cell has grown into one trillion cells: the Giant Great Khali.Each one of us has 50 trillion cells all developed from that 0.1 mm single cell inside our mother’s womb.

( Various stages of development of an human foetus inside the mother’s womb as it grows from a single cell to a new born weighing 3 kg is depicted in sculpture at a Maternity Hospital in Quatar. Video courtesy: social media )

From a sperm and egg cell to a new born ( Quatar)

How big is the number 50 trillion ?

An example: If I take 50 trillion A4 size papers and stack them one on top of other neatly, the height of the whole stack will reach from our earth to the moon and back again. When a RTPCR report gives a CT value of 40, it tells us that the single viral gene molecule has been doubled on and on to the 40th power before its signal could be picked up by our sophisticated lab equipment just like the single cell dividing 40 times to create the Giant Khali. So, just imagine how insignificant is the viral content in that sample ! The lower the CT value, the higher is the concentration of viral gene molecule in the sample.

A CT value of 15-20 is detected by the Rapid Antigen Test. It also indicates significant viral load. RAT positive person can be very infective and should be isolated. RAT is a handy, at-home test that gives a result within 20 minutes. If properly collected, a positive result is very important. Although it can miss a few cases, those cases may have lower viral load and may not spell any disaster to the society. ( Simplified at the cost of fact. )