diff --git a/src/NHapi.Base/Model/Primitive/TSComponentOne.cs b/src/NHapi.Base/Model/Primitive/TSComponentOne.cs
index 2a12073fa..726749346 100644
--- a/src/NHapi.Base/Model/Primitive/TSComponentOne.cs
+++ b/src/NHapi.Base/Model/Primitive/TSComponentOne.cs
@@ -28,6 +28,7 @@ namespace NHapi.Base.Model.Primitive
 {
     using System;
     using System.Globalization;
+    using System.Linq;
     using System.Threading;
 
     /// <summary>
@@ -57,6 +58,26 @@ namespace NHapi.Base.Model.Primitive
     /// </version>
     public class TSComponentOne : AbstractPrimitive
     {
+        /// <summary>
+        /// The remaining DTM precisions, YYYY[MM[DD[HH[MM[SS[.S[S[S[S]]]]]]]]][+/-ZZZZ], that the
+        /// DateTimeFormat properties below do not cover, for example fractional seconds with a time zone offset
+        /// (<c>20230211140114.0000+0800</c>). Tried after those formats, so values that already
+        /// parsed keep their result. A time zone offset is converted to local time, as it already is
+        /// for <see cref="LongDateTimeFormatWithOffset"/>.
+        /// </summary>
+        private static readonly string[] AdditionalDtmFormats =
+        {
+            "yyyy",
+            "yyyyMM",
+            "yyyyMMddHH",
+            "yyyyzzz",
+            "yyyyMMzzz",
+            "yyyyMMddzzz",
+            "yyyyMMddHHzzz",
+            "yyyyMMddHHmmzzz",
+            "yyyyMMddHHmmss.FFFFzzz",
+        };
+
         private CommonTS myDetail;
 
         /// <param name="theMessage">message to which this Type belongs.
@@ -246,7 +267,9 @@ public virtual DateTime GetAsDate()
         {
             try
             {
-                var dateFormats = new string[] { LongDateTimeFormat, ShortDateTimeFormat, LongDateTimeFormatWithSecond, LongDateTimeFormatWithOffset, LongDateTimeFormatWithFractionOfSecond };
+                var dateFormats = new[] { LongDateTimeFormat, ShortDateTimeFormat, LongDateTimeFormatWithSecond, LongDateTimeFormatWithOffset, LongDateTimeFormatWithFractionOfSecond }
+                    .Concat(AdditionalDtmFormats)
+                    .ToArray();
                 var val = DateTime.MinValue;
                 var culture = Thread.CurrentThread.CurrentCulture;
                 if (Value != null && Value.Length > 0)
diff --git a/tests/NHapi.NUnit/DateTypeTest26.cs b/tests/NHapi.NUnit/DateTypeTest26.cs
new file mode 100644
index 000000000..60fbc919f
--- /dev/null
+++ b/tests/NHapi.NUnit/DateTypeTest26.cs
@@ -0,0 +1,86 @@
+namespace NHapi.NUnit
+{
+    using System;
+
+    using global::NUnit.Framework;
+
+    using NHapi.Base;
+    using NHapi.Base.Parser;
+    using NHapi.Model.V26.Datatype;
+    using NHapi.Model.V26.Message;
+
+    [TestFixture]
+    public class DateTypeTest26
+    {
+        private static readonly TimeSpan PlusEight = TimeSpan.FromHours(8);
+
+        private static readonly object[] OffsetCases =
+        {
+            // Fractional seconds with an offset: the Mindray V9 value from issue #411.
+            new object[] { "20230211140114.0000+0800", new DateTimeOffset(2023, 2, 11, 14, 1, 14, PlusEight) },
+            new object[] { "20230211140114.1234+0800", new DateTimeOffset(2023, 2, 11, 14, 1, 14, 123, PlusEight).AddTicks(4000) },
+            new object[] { "20230211140114.5-0530", new DateTimeOffset(2023, 2, 11, 14, 1, 14, 500, TimeSpan.FromMinutes(-330)) },
+            new object[] { "202302111401+0800", new DateTimeOffset(2023, 2, 11, 14, 1, 0, PlusEight) },
+            new object[] { "2023021114+0800", new DateTimeOffset(2023, 2, 11, 14, 0, 0, PlusEight) },
+            new object[] { "20230211+0800", new DateTimeOffset(2023, 2, 11, 0, 0, 0, PlusEight) },
+        };
+
+        private static readonly object[] PrecisionCases =
+        {
+            new object[] { "2023021114", new DateTime(2023, 2, 11, 14, 0, 0) },
+            new object[] { "202302", new DateTime(2023, 2, 1) },
+            new object[] { "2023", new DateTime(2023, 1, 1) },
+        };
+
+        [TestCaseSource(nameof(OffsetCases))]
+        public void GetAsDate_DtmWithOffset_ConvertsToLocalTime(string value, DateTimeOffset expected)
+        {
+            var dtm = new DTM(new ACK()) { Value = value };
+
+            Assert.That(dtm.GetAsDate(), Is.EqualTo(expected.LocalDateTime));
+        }
+
+        [TestCaseSource(nameof(PrecisionCases))]
+        public void GetAsDate_ReducedPrecisionDtm_Parses(string value, DateTime expected)
+        {
+            var dtm = new DTM(new ACK()) { Value = value };
+
+            Assert.That(dtm.GetAsDate(), Is.EqualTo(expected));
+        }
+
+        [TestCase("20230211140114.12345")]
+        [TestCase("2023021114011")]
+        [TestCase("20231311")]
+        [TestCase("not a date")]
+        public void GetAsDate_InvalidDtm_StillThrows(string value)
+        {
+            var dtm = new DTM(new ACK()) { Value = value };
+
+            Assert.Throws<HL7Exception>(() => dtm.GetAsDate());
+        }
+
+        [Test]
+        public void GetAsDate_MindrayOruR01_ParsesMessageAndObservationTimes()
+        {
+            var message =
+                "MSH|^~\\&|MINDRAY_^00B0353000000^EUI-64|MINDRAY|||20230211140114.0000+0800||ORU^R01^ORU_R01|10|P|2.6|||AL|NE||UNICODE UTF-8|||IHE_PCD_001^IHE PCD^1.3.6.1.4.1.19376.1.6.1.1.1^ISO\r"
+                + "PID|||1234^^^Hospital^PI||Uui^Kki^^^^^L|||M\r"
+                + "PV1||I|ED^^RED VS9\r"
+                + "OBR|1|10^MINDRAY_^00B0353000000^EUI-64|10^MINDRAY_^00A037000000^EUI-64|182777000^monitoring of patient^SCT|||20230211134735.0000+0800\r"
+                + "OBX|1|NM|150456^MDC_PULS_OXIM_SAT_O2^MDC|1.3.1.150456|97|262688^MDC_DIM_PERCENT^MDC|||||R|||20230211134735.0000+0800||||00A037000000^^00A037000000^EUI-64\r";
+
+            var oru = (ORU_R01)new PipeParser().Parse(message);
+            var obx = oru.GetPATIENT_RESULT().GetORDER_OBSERVATION().GetOBSERVATION().OBX;
+
+            Assert.Multiple(() =>
+            {
+                Assert.That(
+                    oru.MSH.DateTimeOfMessage.GetAsDate(),
+                    Is.EqualTo(new DateTimeOffset(2023, 2, 11, 14, 1, 14, PlusEight).LocalDateTime));
+                Assert.That(
+                    obx.DateTimeOfTheObservation.GetAsDate(),
+                    Is.EqualTo(new DateTimeOffset(2023, 2, 11, 13, 47, 35, PlusEight).LocalDateTime));
+            });
+        }
+    }
+}