Measuring diagnoses: ICD code accuracy.
OBJECTIVE
To examine potential sources of errors at each step of the described inpatient International Classification of Diseases (ICD) coding process.


METHODS
The use of disease codes from the ICD has expanded from classifying morbidity and mortality information for statistical purposes to diverse sets of applications in research, health care policy, and health care finance. By describing a brief history of ICD coding, detailing the process for assigning codes, identifying where errors can be introduced into the process, and reviewing methods for examining code accuracy, we help code users more systematically evaluate code accuracy for their particular applications.


METHODS
We summarize the inpatient ICD diagnostic coding process from patient admission to diagnostic code assignment. We examine potential sources of errors at each step and offer code users a tool for systematically evaluating code accuracy.


RESULTS
Main error sources along the "patient trajectory" include amount and quality of information at admission, communication among patients and providers, the clinician's knowledge and experience with the illness, and the clinician's attention to detail. Main error sources along the "paper trail" include variance in the electronic and written records, coder training and experience, facility quality-control efforts, and unintentional and intentional coder errors, such as misspecification, unbundling, and upcoding.


CONCLUSIONS
By clearly specifying the code assignment process and heightening their awareness of potential error sources, code users can better evaluate the applicability and limitations of codes for their particular situations. ICD codes can then be used in the most appropriate ways.
O'Malley
Kimberly J
KJ
Pearson Educational Mearsurement, Austin, TX 78758, USA.
Cook
Karon F
KF
Price
Matt D
MD
Wildes
Kimberly Raiford
KR
Hurdle
John F
JF
Ashton
Carol M
CM
D003625:Data Collection / Q000379:methods*; D006302:Health Services Research / Q000379:methods*; D006801:Humans; D038801:International Classification of Diseases; D015203:Reproducibility of Results