Question: Midichlorian's are chemical compounds found within every living cell that forms the basis between the connection life and the Force. Without midichlorians, life would be impossible. The amount of midichlorians in a life form represents its ability to understand, comprehend, and manipulate the Force.

My name is Darth Incognitus, and I have decided to absorb more of these cells into my own body to make my force sensitive abilities stronger. To accomplish this, I have kidnapped numerous force sensitive users who match my blood type. When their midichlorian count has been measured, I will perform a blood transfusion from them to myself in order to absorb these cells. After I have attained enough of these cells, I will become the most powerful force user in the world and create my Sith empire. Then, I will use this method to strengthen my apprentices and students.

However, after a number of tries, I have noticed that my powers have not increased. No matter how many Jedi I murder and drain of blood, my abilities remain average. Why would this be the case?

Answer: 
**When in trouble, in sci-fy, put a machine to do it for you**

What that mean is basically a reminder than Darth Vader was a reality, and Star Wars have A TON of technology designed to replace organs and/or keep alive people.

With that in mind, you, oh so great Darth Incognitus need a machine than allow you control the response of your body against it's midiclorians.

If the force or your body stand in the way of you being more powerfull, You need to control them!

If you need an automatic control of your natural filtering organs, they can be replaced by synthetic versions of them specialy modified to make your midiclorian administration as you want.

What happend? your blood cells are not designed to resist the influx of new Midichlorian? doesn't matter, replace the medula of your bones (which if i remember correctly, replace the blood lossed) for a machine than do replace blood BUT make it just in the way you need it for achieve your "Darth intentions" (pun intended).

Is your brain affecting the process? doesn't matter, put an artificial part of your brain than do exactly what your brain used to do OR put a machine than counterweight the efect of that part of your brain just in the right way to make the effect you want.

**In time you'll become more and more of a machine Darth Incognitus!, but we all know than Power only respond to Inmortality! and all we know than Machines are inmortal!**

PS: if you like my answer and are making something related to starwars, make a character kinda like a teck-priest and put the name 'Kradathon' in some way connected to it, you decide what the name means, it would be a cool way to say "thanks". :D
Midichlorian's are not the bottleneck in this equation. Your body and brain have developed "Force pathways" to make use of the amount of Midichlorian's you naturally have in your blood. They finished developing at the age of 16. You can add all the chemicals you want to your blood now, but your body and brain simply can't use them for anything--they can't handle that much Force.

Now if you'd started these transfusions before you turned 16 and your body finished developing it's Force pathways though... Have you thought about creating a test experiment heir to your power?