R76.8Other specified abnormal immunological findings in serum

R76.8 is the ICD-10-CM diagnosis code for other specified abnormal immunological findings in serum. It belongs to category R76 (other abnormal immunological findings in serum), block R70-R79 (abnormal findings on examination of blood, without diagnosis) and chapter 18 (symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified). It is a header code, so it can't be reported by itself; one of its 2 subcodes must be used instead.

Within R76, choose R76.8 (Other specified abnormal immunological findings in serum) only when documentation doesn't support a more specific option: raised antibody titer (R76.0), nonspecific reaction to test for tuberculosis (R76.1) and abnormal immunological finding in serum, unspecified (R76.9).

To report this condition, pick the subcode that matches the documentation: R76.81 (arthritis) and R76.89 (serum).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015, and changed in FY2026 (expanded into subcodes).

Before ICD-10, this condition was coded in ICD-9-CM as 795.6 (false positive serological test for syphilis) and 795.79 (other and unspecified nonspecific immunological findings).