diff --git a/src/Elastic.Apm/Model/DroppedSpanStats.cs b/src/Elastic.Apm/Model/DroppedSpanStats.cs
index 2254a6f78..63121a0be 100644
--- a/src/Elastic.Apm/Model/DroppedSpanStats.cs
+++ b/src/Elastic.Apm/Model/DroppedSpanStats.cs
@@ -3,6 +3,7 @@
 // Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information
 
+using System;
 using Elastic.Apm.Api;
 using Elastic.Apm.Libraries.Newtonsoft.Json;
 
@@ -18,7 +19,7 @@ public DroppedSpanStats(string serviceTargetType, string serviceTargetName, stri
 			double durationSumUs
 		)
 		{
-			Duration = new DroppedSpanDuration { Count = 1, Sum = new DroppedSpanDuration.DroppedSpanDurationSum { Us = durationSumUs } };
+			Duration = new DroppedSpanDuration { Count = 1, Sum = new DroppedSpanDuration.DroppedSpanDurationSum { UsRaw = durationSumUs } };
 			ServiceTargetType = serviceTargetType;
 			ServiceTargetName = serviceTargetName;
 			DestinationServiceResource = destinationServiceResource;
@@ -49,7 +50,6 @@ double durationSumUs
 		/// </summary>
 		public Outcome Outcome { get; }
 
-
 		/// <summary>
 		/// Duration holds duration aggregations about the dropped span.
 		/// </summary>
@@ -63,13 +63,17 @@ internal class DroppedSpanDuration
 			public int Count { get; set; }
 
 			/// <summary>
-			///  Sum holds dimensions about the dropped span's duration.
+			/// Sum holds dimensions about the dropped span's duration.
 			/// </summary>
 			public DroppedSpanDurationSum Sum { get; set; }
 
 			internal class DroppedSpanDurationSum
 			{
-				public double Us { get; set; }
+				[JsonIgnore]
+				public double UsRaw { get; set; }
+
+				// As `duration.sum.us` is an integer in the intake API we round during serialization.
+				public int Us => Convert.ToInt32(UsRaw);
 			}
 		}
 	}
diff --git a/src/Elastic.Apm/Model/Transaction.cs b/src/Elastic.Apm/Model/Transaction.cs
index c1f401d59..c80f962e2 100644
--- a/src/Elastic.Apm/Model/Transaction.cs
+++ b/src/Elastic.Apm/Model/Transaction.cs
@@ -575,7 +575,7 @@ double duration
 					new DroppedSpanStats.DroppedSpanDuration { Sum = new DroppedSpanStats.DroppedSpanDuration.DroppedSpanDurationSum() };
 
 				item.Duration.Count++;
-				item.Duration.Sum.Us += duration;
+				item.Duration.Sum.UsRaw += duration;
 			}
 			else
 			{
diff --git a/test/Elastic.Apm.Tests/DroppedSpansStatsTests.cs b/test/Elastic.Apm.Tests/DroppedSpansStatsTests.cs
index e01434844..e0cd2453e 100644
--- a/test/Elastic.Apm.Tests/DroppedSpansStatsTests.cs
+++ b/test/Elastic.Apm.Tests/DroppedSpansStatsTests.cs
@@ -60,7 +60,7 @@ public void SingleDroppedSpanTest()
 				//This span will be dropped
 				var span1 = transaction.StartSpan("foo", "bar", isExitSpan: true);
 				span1.Context.Http = new Http { Method = "GET", StatusCode = 200, Url = "https://foo.bar" };
-				span1.Duration = 100;
+				span1.Duration = 100.001;
 				span1.End();
 
 				transaction.End();
@@ -75,7 +75,7 @@ public void SingleDroppedSpanTest()
 			payloadSender.FirstTransaction.DroppedSpanStats.First().ServiceTargetType.Should().Be("bar");
 			payloadSender.FirstTransaction.DroppedSpanStats.First().Outcome.Should().Be(Outcome.Success);
 			payloadSender.FirstTransaction.DroppedSpanStats.First().Duration.Count.Should().Be(1);
-			payloadSender.FirstTransaction.DroppedSpanStats.First().Duration.Sum.Us.Should().Be(100);
+			payloadSender.FirstTransaction.DroppedSpanStats.First().Duration.Sum.Us.Should().Be(100); // This should be rounded and will be sent in the JSON
 		}
 
 		[Fact]
@@ -130,22 +130,22 @@ public void MultipleDroppedSpanTest()
 
 			payloadSender.FirstTransaction.DroppedSpanStats.Should()
 				.Contain(n => n.Outcome == Outcome.Success
-					&& n.Duration.Count == 2 && Math.Abs(n.Duration.Sum.Us - 250) < 1 && n.DestinationServiceResource == "foo.bar:443"
+					&& n.Duration.Count == 2 && Math.Abs(n.Duration.Sum.UsRaw - 250) < 1 && n.DestinationServiceResource == "foo.bar:443"
 					&& n.ServiceTargetName == "foo.bar:443" && n.ServiceTargetType == "bar");
 
 			payloadSender.FirstTransaction.DroppedSpanStats.Should()
 				.Contain(n => n.Outcome == Outcome.Failure
-					&& n.Duration.Count == 1 && Math.Abs(n.Duration.Sum.Us - 50) < 1 && n.DestinationServiceResource == "foo.bar:443"
+					&& n.Duration.Count == 1 && Math.Abs(n.Duration.Sum.UsRaw - 50) < 1 && n.DestinationServiceResource == "foo.bar:443"
 					&& n.ServiceTargetName == "foo.bar:443" && n.ServiceTargetType == "bar");
 
 			payloadSender.FirstTransaction.DroppedSpanStats.Should()
 				.Contain(n => n.Outcome == Outcome.Success
-					&& n.Duration.Count == 1 && Math.Abs(n.Duration.Sum.Us - 15) < 1 && n.DestinationServiceResource == "foo2.bar:443"
+					&& n.Duration.Count == 1 && Math.Abs(n.Duration.Sum.UsRaw - 15) < 1 && n.DestinationServiceResource == "foo2.bar:443"
 					&& n.ServiceTargetName == "foo2.bar:443" && n.ServiceTargetType == "bar");
 
 			payloadSender.FirstTransaction.DroppedSpanStats.Should()
 				.Contain(n => n.Outcome == Outcome.Success
-					&& n.Duration.Count == 50 && Math.Abs(n.Duration.Sum.Us - 50 * 50) < 1 && n.DestinationServiceResource == "mysql");
+					&& n.Duration.Count == 50 && Math.Abs(n.Duration.Sum.UsRaw - 50 * 50) < 1 && n.DestinationServiceResource == "mysql");
 		}
 
 		/// <summary>
diff --git a/test/Elastic.Apm.Tests/SerializationTests.cs b/test/Elastic.Apm.Tests/SerializationTests.cs
index cfe8586a2..9a76672c8 100644
--- a/test/Elastic.Apm.Tests/SerializationTests.cs
+++ b/test/Elastic.Apm.Tests/SerializationTests.cs
@@ -495,7 +495,7 @@ public void DroppedSpanStatsTest()
 			transaction.End();
 
 			var json = _payloadItemSerializer.Serialize(transaction);
-			json.Should().Contain("\"duration\":{\"count\":1,\"sum\":{\"us\":100.0}}");
+			json.Should().Contain("\"duration\":{\"count\":1,\"sum\":{\"us\":100}}");
 		}
 
 		/// <summary>