in which the tissue characteristic includes a tissue impedance it can be determined at 606 whether a change in tissue impedance of the orthogonal vector is less than a change in tissue impedance of the non orthogonal vector and if so then at 608 the fluid accumulation is declared to be associated with local fluid in the lungs and otherwise at 610 the fluid accumulation is declared to not be associated with local fluid in the lungs e g such as can arise from pneumonia but instead associated with fluid elsewhere e g global fluid overload such as associated with a chf decompensation episode information about or based on whether the fluid accumulation is local to the lungs e g fluid presence fractional change in impedance indication of pneumonia chf decompensation etc can be communicated to a user or automated process such as to provide a diagnostic indication or for use in controlling a therapy provided by the crm device 100 e g cardiac resynchronization therapy crt by another implanted ambulatory or other medical device or by a physician or other caregiver such communication can be internal to the electronics unit 102 of the crm device 100 or can involve communication with the local interface 123 or with the remote interface 124 the acts described in fig6 can be.