diff --git a/src/ontology/obi-edit.owl b/src/ontology/obi-edit.owl
index 7d41951e..34a754c0 100644
--- a/src/ontology/obi-edit.owl
+++ b/src/ontology/obi-edit.owl
@@ -21937,6 +21937,30 @@ b) that the amount of analyte/measurand detected is over some predetermined thre
     
 
 
+    <!-- http://purl.obolibrary.org/obo/OBI_0003652 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/OBI_0003652">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/OBI_0100017"/>
+        <rdfs:subClassOf>
+            <owl:Restriction>
+                <owl:onProperty rdf:resource="http://purl.obolibrary.org/obo/BFO_0000051"/>
+                <owl:allValuesFrom>
+                    <owl:Class>
+                        <owl:complementOf rdf:resource="http://purl.obolibrary.org/obo/PR_000003918"/>
+                    </owl:Class>
+                </owl:allValuesFrom>
+            </owl:Restriction>
+        </rdfs:subClassOf>
+        <obo:IAO_0000111>albumin-free serum</obo:IAO_0000111>
+        <obo:IAO_0000115>A blood serum specimen that contains no albumin.</obo:IAO_0000115>
+        <obo:IAO_0000117>Sebastian Duesing</obo:IAO_0000117>
+        <obo:IAO_0000233>https://github.com/obi-ontology/obi/issues/493</obo:IAO_0000233>
+        <obo:IAO_0000234>Philippe Rocca-Serra</obo:IAO_0000234>
+        <rdfs:label xml:lang="en">albumin-free serum</rdfs:label>
+    </owl:Class>
+    
+
+
     <!-- http://purl.obolibrary.org/obo/OBI_0005246 -->
 
     <owl:Class rdf:about="http://purl.obolibrary.org/obo/OBI_0005246">