So, you know you’re looking at management options for adults with stage 5 chronic kidney disease, but do you want to be specific about how you know these adults actually have this condition? In other words… how were they diagnosed?

For example, kidney function is best measured by something called the glomerular filtration rate (GFR) which basically describes the amount of waste your kidneys can filter at one time. When your GFR gets low, it means your kidneys aren’t working well, and if your GFR gets really low, it means your kidneys may stop working and you’ll need some type of intervention.

But measuring GFR is difficult and complicated. It’s easier to plug the results of a simple blood test into a mathematical formula to get a good estimate of your GFR.

This begs the question: do you want the populations in your studies to be diagnosed using a direct measurement of GFR or is a blood test approximating their GFR good enough?

Of course, this is a simplified example of how kidney disease is diagnosed. For more information about kidney disease, talk to your doctor.

You don’t need to include this level of specificity in your question, but it should be part of your research plan.