Correct primary ICD-9

What would be the correct icd-9 code to use as primary to 95811 (sleep study)?
Out of these common 780.79 799.02 786.05 327.23.
And is the order of the icd-9's matter?

re: Correct primary ICD-9

The primary dx are the codes that are on the pt's script from the referring physician. After the study is read you can then add the dx codes that the interpreting physician assigns if the study is positive. If negative the dx from referring phy are the only codes.