What does it mean when my "platelet count" is 144?

It's normal!: The range for normal platelets is between 150 and 300 in most labs. Your count of 144 is shorthand for 144,000 platelets per microliter of blood in your body. A microliter is about the tiniest water droplet you could see with your naked eye, about the size of the period in this sentence. So your count of 144 is just a little lower than normal, but not enough that I would be concerned.