The 7110.65 is your friend...
2-1-8. MINIMUM FUEL
If an aircraft declares a state of “minimum fuel,”
inform any facility to whom control jurisdiction is
transferred of the minimum fuel problem and be alert
for any occurrence which might delay the aircraft
enroute.
NOTE
Use of the term “minimum fuel” indicates recognition by
a pilot that his/her fuel supply has reached a state where,
upon reaching destination, he/she cannot accept any undue
delay. This is not an emergency situation but merely an
advisory that indicates an emergency situation is possible
should any undue delay occur. A minimum fuel advisory
does not imply a need for traffic priority. Common sense
and good judgment will determine the extent of assistance
to be given in minimum fuel situations. If, at any time, the
remaining usable fuel supply suggests the need for traffic
priority to ensure a safe landing, the pilot should declare
an emergency and report fuel remaining in minutes