Is positive d dimer accurate in predicting pe in 92 yo person? what test should then be done?

See below: A positive d-dimer is suggestive but not diagnostic or accurate. Chronic diseases and acute illnesses can raise it too. It's only useful if it's low - to rule out a clot. If there's a positive d-dimer and suspicion for clot, an ultrasound of the legs should be done. If suspicion for a lung clot, a ct angiogram or v/q scan of the chest is indicated.

See below: Renal function in a 92 y/o is compromised just because of age, so d-dimer may not be entirely accurate. If a pe is truly suspected, the gold standard is doing a ct chest with contrast. Again, a 92 y/o is more susceptible to kidney injury because of the above. An alternative is doing a v/q scan, if the patient is capable of cooperating, and us of legs to r/o dvt. Balance risk vs benefit!