The CPT code 87070 refers to a fundamental microbiological procedure: the aerobic bacterial culture of specimens from sources other than blood. This test is essential for diagnosing bacterial infections in various clinical sites, including but not limited to wounds, abscesses, body fluids (such as cerebrospinal, pleural, peritoneal, or synovial fluid), and tissue biopsies. The process begins with the careful collection of a specimen using sterile techniques to avoid contamination by commensal flora. Once the specimen arrives at the laboratory, it is inoculated onto appropriate primary culture media, such as sheep blood agar, chocolate agar, and MacConkey agar. These media are selected to support the growth of a wide range of aerobic and facultatively anaerobic pathogens while suppressing others. The plates are incubated at 35 to 37 degrees Celsius in an atmosphere containing 5% to 10% carbon dioxide or ambient air for 24 to 72 hours. Laboratory personnel perform daily visual inspections of the media for signs of microbial growth, noting colony morphology, color, and density. Upon detecting growth, a Gram stain is performed to determine the bacterial shape and cell wall characteristics. Presumptive identification is then achieved through simple biochemical tests such as catalase, oxidase, or coagulase. It is important to note that 87070 covers the isolation and presumptive identification only; definitive identification and antibiotic susceptibility testing are reported using separate CPT codes. This culture is a critical diagnostic tool in managing acute and chronic infections, guiding initial empiric therapy and ensuring appropriate clinical intervention. This code is specifically designated for sources other than blood, stool, or urine, which have dedicated codes, allowing for standardized identification of pathogens from diverse anatomical sites.