BMLT or Bachelor of Medical Lab Technology is a 3 years Undergraduate course which is of 3 year duration and the eligibility criteria for the course is stated below-

Successful completion of 10+2 in Science (physics, chemistry and biology) with an aggregate of 50 per cent of marks from a recognised board.

The admission to most of the colleges are on the basis of 10+2 score.

Now as you can see that PCB is required for the course so if you are a PCM student and didn't have biology then you aren't eligible for the course. If you are a PCMB student, then also you are eligible.

For more information regarding BMLT consider the link below:

https://www.careers360.com/courses/bmlt-bachelor-in-medical-laboratory-technology

I hope this helps. Wish you a great day!