Blood spot profiles are an excellent way of monitoring 17OHP levels over a period of 24 hours, without the necessity of a hospital admittance.  A random test for 17OHP is of little use as it does not show how the levels fluctuate throughout the day.  For instance my son’s last profile showed a raised level at the 10pm spot, showing that he needed an increase of his dose in the afternoon but that his morning dose and evening dose were perfectly sufficient.  Without these, it must be difficult for specialists to know which dose to increase and a random test taken at the wrong time would have shown adequate control!  As to how long it takes to get results depends on the hospital it is sent to and whether your specilsit marks it as ’urgent’.  In the UK it can take 24 hours or as long as 4 weeks!  I tend to do these about every 2-3 months (as my son is in puberty) but generally twice yearly is considered sufficient.  We also had the choice of doing saliva profiles but my son is quite happy with the blood ones although I believe the saliva ones are less traumatic for small children, but it can be a bit messy!