Use of ICD-10 diagnosis codes to identify seropositive and seronegative rheumatoid arthritis when lab results are not available

Study of seropositivity in RA patients in the RISE (43,581) registry & Marketscan pts (1185) showed ICD10 Coding with M05 had a sensitivity = 0.73- 0.76, & PPV = 0.82 -0.84 for seropositive RA. Good but does that mean Ya'll are miscoding 25% of you