The current active/selected admin color scheme is a user setting, you can get its value with
get_user_option( 'admin_color' ).
$admin_color = get_user_option( 'admin_color' );
if you want to access the color scheme for the specific user then pass the user id as second parameter in the
$user1_id = 2;
$user1_color = get_user_option( 'admin_color', $user1_id );
the above both examples will return the name of the active color scheme e.g; blue, fresh, Midnight etc..
if you want to access the whole list of colors used in the admin section then use the following..
$admin_colors = $_wp_admin_css_colors;