How accurately can one test CPT conservation with reactor and solar   neutrino experiments?
  We show that the combined data from solar neutrino experiments and from the KamLAND reactor neutrino experiment can establish an upper limit on, or detect, potential CPT violation in the neutrino sector of order 10^{-20} GeV to 10^{-21} GeV. 
John N. Bahcall, V. Barger, Danny Marfatia