The invention provides a diagnostics assay for measuring the responsiveness to a drug by comparing the mRNA levels of a gene that responds to the drug, such as a steroid, to the mRNA levels of a gene that does not respond to the drug. Methods according to the invention are useful for predicting the ability of a patient (or a tissue, body fluid or cell sample in vitro) to respond to a drug or steroid at any stage of their treatment (i.e., before, during or after), and to monitor the patient (or a tissue, body fluid or cell) over time to assess continued responsiveness to the drug or steroid.