Correlating two variables Im doing a medical research in which i have a cohort of 59 patients. I have data for each one about their blood level of a specific marker and data for each one about how many organs the disease I'm researching has affected. Basically I want to see whether or not the disease extension (how many organs are affected) is correlated with a high value of the said marker in the blood. Would using a spearman correlation be the correct strategy here?

You can always use correlation in a problem like this.
I guess there could be some problems if the dispersion of the marker (a continuous variable) is very high and the dispersion organ count is very low (i.e. a lot of observations having a low count like 1 or 2). Anyway, in such a case you can still use correlation but it would yield a low number.
If you want to get more fancy you can try a regression with a categorical dependent variable (the organ count). Poisson regression might be best.
