You can have a Hair Mineral Test, but I have not heard of scalp analysis.
There are many reasons why you may have slow hair growth. One of the reasons may be your genetic predisposition. However, stress, poor diet and some medical conditions such as under-active thyroid may be one or a combination of reasons.
It is a good idea first of all to speak with your GP and ask to check your Thyroid Function and discuss any other medical reasons. If everything is OK with your health, you could try mesotherapy. Our clients are very happy with the results, but regular maintenance is required. Also try Nurkin vitamin supplement for Hair - available from most health shops.
On the positive side, if you are happy with the sickness and the condition of hair and you are not losing it, but only the growth is slow, you are saving quite a lot on hair cuts. My hair growth is too fast. I have to visit my hair dresser every 2-3 weeks, which I don't find that very convenient :-)
I hope the above is helpful
Harley Medical Aestheticshttp://www.cdt3000.co.uk