diff --git a/src/main/java/ATCCodes/AtcCode.java b/src/main/java/ATCCodes/AtcCode.java
index e8bf9f1..deb1419 100644
--- a/src/main/java/ATCCodes/AtcCode.java
+++ b/src/main/java/ATCCodes/AtcCode.java
@@ -48,4 +48,15 @@ public class AtcCode implements AgentCode {
     public int hashCode() {
         return Objects.hash(code.toLowerCase(), name.toLowerCase());
     }
+
+    /**
+     * Prüft auf gültiges ATCCode-Schema ab Ebene 2
+     * @param code Der zu prüfende Code
+     * @return Gibt <code>true</code> zurück, wenn der angegebene Code dem ATCCode-Schema entspricht
+     */
+    public static boolean isAtcCode(String code) {
+        return null != code
+                && ! code.isBlank()
+                && code.matches("[ABCDGHJLMNPRSV][0-2][1-9]([A-Z]([A-Z]([0-9]{2})?)?)?");
+    }
 }
\ No newline at end of file
diff --git a/src/main/java/ATCCodes/services/OnkostarAgentCodeService.java b/src/main/java/ATCCodes/services/OnkostarAgentCodeService.java
index f29f074..e0c75f4 100644
--- a/src/main/java/ATCCodes/services/OnkostarAgentCodeService.java
+++ b/src/main/java/ATCCodes/services/OnkostarAgentCodeService.java
@@ -1,6 +1,7 @@
 package ATCCodes.services;
 
 import ATCCodes.AgentCode;
+import ATCCodes.AtcCode;
 import ATCCodes.UnregisteredCode;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.stereotype.Service;
@@ -47,8 +48,14 @@ public class OnkostarAgentCodeService implements AgentCodeService {
         return jdbcTemplate.query(
                 sql,
                 new Object[]{query + "%", "%" + query + "%", "%" + query + "%"},
-                (resultSet, i) ->
-                        new UnregisteredCode(resultSet.getString("code"), resultSet.getString("shortdesc"))
+                (resultSet, i) -> {
+                    var code = resultSet.getString("code");
+                    var shortdesc = resultSet.getString("shortdesc");
+                    if (AtcCode.isAtcCode(code)) {
+                        return new AtcCode(code, shortdesc);
+                    }
+                    return new UnregisteredCode(code, shortdesc);
+                }
         );
     }
 }
\ No newline at end of file
diff --git a/src/test/java/ATCCodes/AtcCodeTest.java b/src/test/java/ATCCodes/AtcCodeTest.java
new file mode 100644
index 0000000..c00e499
--- /dev/null
+++ b/src/test/java/ATCCodes/AtcCodeTest.java
@@ -0,0 +1,28 @@
+package ATCCodes;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class AtcCodeTest {
+
+    @Test
+    void testShouldDetectAtcCodeScheme() {
+        assertTrue(AtcCode.isAtcCode("L01"));
+        assertTrue(AtcCode.isAtcCode("L01A"));
+        assertTrue(AtcCode.isAtcCode("L01AA"));
+        assertTrue(AtcCode.isAtcCode("L01AA01"));
+    }
+
+    @Test
+    void testShouldDetectInvalidAtcCodeScheme() {
+        assertFalse(AtcCode.isAtcCode(null));
+        assertFalse(AtcCode.isAtcCode("  "));
+        assertFalse(AtcCode.isAtcCode("irgendwas"));
+        assertFalse(AtcCode.isAtcCode("L00AA"));
+        assertFalse(AtcCode.isAtcCode("Z01AA"));
+        assertFalse(AtcCode.isAtcCode("L01AA0"));
+    }
+
+}