250.80 Diabetes with other specified manifestations, type II or unspecified type, not stated as uncontrolled
731.8 Other bone involvement in diseases classified elsewhere
730.27 Unspecified osteomyelitis, ankle and foot
Starting with the word “Amputation” in the CPT index, look for the subterm “foot,” which directs the coder to range 28800-28805. After reviewing the codes in the range, code 28805 was selected since it describes the procedure outlined in the operative report, and includes the transmetatarsal amputation having been mapped out on the patient’s skin. The procedure involves removal of the right forefoot and, therefore, it is appropriate to append HCPCS Level II modifier RT (right) to the CPT code.
The procedure was necessitated by osteomyelitis of the foot due to underlying diabetes. Look in the ICD-9-CM alphabetical index under the main term “Diabetes” and the subterms “complication” and “specified, NEC,” which leads to 250.8. This code requires completion with a fifth-digit subclassification to indicate the specific type and level of control of the disease. Since the type of diabetes (type I or type II) is not documented and neither is the status of the diabetes control, fifth-digit subclassification of “0” is reported.
According to ICD-9-CM guidelines (see AHA Coding Clinic, fourth quarter, 1997), the appropriate code for the diabetes is sequenced first. When verifying this code in the tabular section, an instructional note states to use an additional code to identify any manifestations, such as an ulcer or diabetic bone changes, which is reported with 731.8. Turning to this code in the tabular section, another note associated with it directs coders to also report a third code for the specific bone condition, such as osteomyelitis.
Osteomyelitis is defined as an infection of the bone or bone marrow. Look for main term “osteomyelitis” in the alphabetical index of the ICD-9-CM book. Note that the code listed is 730.2 with an icon indicating that a fifth-digit subclassification is required for complete specificity. Fifth-digit options are listed to identify the anatomic site involved. In this case it is the foot, which is reported with fifth digit “7.” Confirmation in the tabular index validates the condition is unspecified osteomyelitis of the ankle and foot. A note under subcategory 730.2 also advises the coder to report an additional code to identify any osseous defect, if applicable.
It should be noted that “unspecified” codes are generally discouraged. Coders should always query a provider in order to obtain information necessary to report a diagnosis as completely as possible and minimize the use of “unspecified “ generic type codes.