If blood cultures are taken because there is a suspicion of sepsis, does it particularly matter if urine cultures are not also taken? why?

See below: Urinary tract infection is one of the most common causes of sepsis, especially in the elderly. Diagnosis of sepsis is based on clinical criteria (mental status, blood pressure, respiratory and heart rates, fever, white cell count, lactate) and not on blood cultures which are often negative. If UTI is the cause, then urine culture will identify bacteria and guide appropriate antibiotic therapy.

Blood cultures: Sepsis is a condition where a local infection has spread to the bloodstream; the process does not normally show any telltale signs in the urine UNLESS the source of the infection is suspected to be the bladder or the kidney. However, statistically, at your age, infection in the genitourinaty tract is often the most likely source, so, if that is suspected, a urine sample is indicated to confirm.