This code system http://terminology.hl7.org/CodeSystem/ex-diagnosis-on-admission defines the following codes:

Code Display Definition
y Yes Diagnosis was present at time of inpatient admission.
n No Diagnosis was not present at time of inpatient admission.
u Unknown Documentation insufficient to determine if condition was present at the time of inpatient admission.
w Undetermined Clinically undetermined. Provider unable to clinically determine whether the condition was present at the time of inpatient admission.
<status value="draft"/> <experimental value="false"/> <date value="2025-09-13T16:46:03-04:00"/> <publisher value="Financial Management"/> <contact> <name value="Financial Management"/> <telecom> <system value="url"/> <value value="http://www.hl7.org/Special/committees/fm"/> </telecom> </contact> <description value="This value set includes example Diagnosis on admission codes."/> <jurisdiction> <coding> <system value="http://unstats.un.org/unsd/methods/m49/m49.htm"/> <code value="001"/> <display value="World"/> </coding> </jurisdiction> <copyright value="These codes have been appropriated from the [UB04 code set](http://www.nubc.org/) owned and managed by the [AHA](http://www.aha.org/). Users require a [license from the AHA](http://www.nubc.org/licensing/index.dhtml) in order to use these codes. **Note: the codes have been withdrawn in a later version**"/> <caseSensitive value="true"/> <content value="complete"/> <concept> <code value="y"/> <display value="Yes"/> <definition value="Diagnosis was present at time of inpatient admission."/> </concept> <concept> <code value="n"/> <display value="No"/> <definition value="Diagnosis was not present at time of inpatient admission."/> </concept> <concept> <code value="u"/> <display value="Unknown"/> <definition value="Documentation insufficient to determine if condition was present at the time of inpatient admission."/> </concept> <concept> <code value="w"/> <display value="Undetermined"/> <definition value="Clinically undetermined. Provider unable to clinically determine whether the condition was present at the time of inpatient admission."/> </concept> </CodeSystem>