diff --git a/src/Fluxera.Entity/Entity.cs b/src/Fluxera.Entity/Entity.cs
index bb2bb3b..1296c1b 100644
--- a/src/Fluxera.Entity/Entity.cs
+++ b/src/Fluxera.Entity/Entity.cs
@@ -56,7 +56,7 @@ public virtual bool IsTransient
 		{
 			get
 			{
-				bool isTransient = Equals(this.ID, default);
+				bool isTransient = Equals(this.ID, default(TKey));
 
 				if(typeof(TKey) == typeof(string))
 				{
diff --git a/tests/Fluxera.Entity.UnitTests/EmployeeAggregate/EmployeeGuid.cs b/tests/Fluxera.Entity.UnitTests/EmployeeAggregate/EmployeeGuid.cs
new file mode 100644
index 0000000..0527ece
--- /dev/null
+++ b/tests/Fluxera.Entity.UnitTests/EmployeeAggregate/EmployeeGuid.cs
@@ -0,0 +1,17 @@
+namespace Fluxera.Entity.UnitTests.EmployeeAggregate
+{
+	using System;
+	using JetBrains.Annotations;
+
+	[PublicAPI]
+	public class EmployeeGuid : AggregateRoot<EmployeeGuid, Guid>
+	{
+		[DomainSignature]
+		public string Name { get; set; }
+
+		[DomainSignature]
+		public int EmployeeNumber { get; set; }
+
+		public decimal Salary { get; set; }
+	}
+}
diff --git a/tests/Fluxera.Entity.UnitTests/EntityExtensionsTests.cs b/tests/Fluxera.Entity.UnitTests/EntityExtensionsTests.cs
index 90f9926..9c1462f 100644
--- a/tests/Fluxera.Entity.UnitTests/EntityExtensionsTests.cs
+++ b/tests/Fluxera.Entity.UnitTests/EntityExtensionsTests.cs
@@ -1,66 +1,20 @@
 namespace Fluxera.Entity.UnitTests
 {
 	using System;
-	using EmployeeAggregate;
 	using FluentAssertions;
+	using Fluxera.Entity.UnitTests.EmployeeAggregate;
 	using NUnit.Framework;
 
 	[TestFixture]
 	public class EntityExtensionsTests
 	{
 		[Test]
-		public void ShouldReturnTrueForTransientEntityForDefaultValue()
-		{
-			Employee employee = new Employee
-			{
-				Name = "James Bond",
-				EmployeeNumber = 8051007,
-				Salary = 1_000_000,
-			};
-
-			employee.IsTransient.Should().BeTrue();
-		}
-
-		[Test]
-		public void ShouldReturnTrueForTransientEntityForNull()
-		{
-			Employee employee = new Employee
-			{
-				ID = null,
-				Name = "James Bond",
-				EmployeeNumber = 8051007,
-				Salary = 1_000_000,
-			};
-
-			employee.IsTransient.Should().BeTrue();
-		}
-
-		[Test]
-		public void ShouldReturnTrueForTransientEntityForEmpty()
-		{
-			Employee employee = new Employee
-			{
-				ID = string.Empty,
-				Name = "James Bond",
-				EmployeeNumber = 8051007,
-				Salary = 1_000_000,
-			};
-
-			employee.IsTransient.Should().BeTrue();
-		}
-
-		[Test]
-		public void ShouldReturnTrueForTransientEntityForOnlyWhitespace()
+		[TestCase(typeof(Employee), true)]
+		[TestCase(typeof(PerformanceReview), false)]
+		[TestCase(typeof(object), false)]
+		public void IsAggregateRootShouldReturnExpectedValue(Type type, bool expected)
 		{
-			Employee employee = new Employee
-			{
-				ID = "     ",
-				Name = "James Bond",
-				EmployeeNumber = 8051007,
-				Salary = 1_000_000,
-			};
-
-			employee.IsTransient.Should().BeTrue();
+			type.IsAggregateRoot().Should().Be(expected);
 		}
 
 		[Test]
@@ -71,14 +25,5 @@ public void IsEntityShouldReturnExpectedValue(Type type, bool expected)
 		{
 			type.IsEntity().Should().Be(expected);
 		}
-
-		[Test]
-		[TestCase(typeof(Employee), true)]
-		[TestCase(typeof(PerformanceReview), false)]
-		[TestCase(typeof(object), false)]
-		public void IsAggregateRootShouldReturnExpectedValue(Type type, bool expected)
-		{
-			type.IsAggregateRoot().Should().Be(expected);
-		}
 	}
 }
diff --git a/tests/Fluxera.Entity.UnitTests/EntityWithGuidKeyTransientTests.cs b/tests/Fluxera.Entity.UnitTests/EntityWithGuidKeyTransientTests.cs
new file mode 100644
index 0000000..c768fc1
--- /dev/null
+++ b/tests/Fluxera.Entity.UnitTests/EntityWithGuidKeyTransientTests.cs
@@ -0,0 +1,38 @@
+namespace Fluxera.Entity.UnitTests
+{
+	using System;
+	using FluentAssertions;
+	using Fluxera.Entity.UnitTests.EmployeeAggregate;
+	using NUnit.Framework;
+
+	[TestFixture]
+	public class EntityWithGuidKeyTransientTests
+	{
+		[Test]
+		public void ShouldReturnTrueForTransientEntityForDefaultValue()
+		{
+			EmployeeGuid employee = new EmployeeGuid
+			{
+				Name = "James Bond",
+				EmployeeNumber = 8051007,
+				Salary = 1_000_000,
+			};
+
+			employee.IsTransient.Should().BeTrue();
+		}
+
+		[Test]
+		public void ShouldReturnTrueForTransientEntityForEmpty()
+		{
+			EmployeeGuid employee = new EmployeeGuid
+			{
+				ID = Guid.Empty,
+				Name = "James Bond",
+				EmployeeNumber = 8051007,
+				Salary = 1_000_000,
+			};
+
+			employee.IsTransient.Should().BeTrue();
+		}
+	}
+}
diff --git a/tests/Fluxera.Entity.UnitTests/EntityWithStringKeyTransientTests.cs b/tests/Fluxera.Entity.UnitTests/EntityWithStringKeyTransientTests.cs
new file mode 100644
index 0000000..48a5ec1
--- /dev/null
+++ b/tests/Fluxera.Entity.UnitTests/EntityWithStringKeyTransientTests.cs
@@ -0,0 +1,65 @@
+namespace Fluxera.Entity.UnitTests
+{
+	using FluentAssertions;
+	using Fluxera.Entity.UnitTests.EmployeeAggregate;
+	using NUnit.Framework;
+
+	[TestFixture]
+	public class EntityWithStringKeyTransientTests
+	{
+		[Test]
+		public void ShouldReturnTrueForTransientEntityForDefaultValue()
+		{
+			Employee employee = new Employee
+			{
+				Name = "James Bond",
+				EmployeeNumber = 8051007,
+				Salary = 1_000_000,
+			};
+
+			employee.IsTransient.Should().BeTrue();
+		}
+
+		[Test]
+		public void ShouldReturnTrueForTransientEntityForEmpty()
+		{
+			Employee employee = new Employee
+			{
+				ID = string.Empty,
+				Name = "James Bond",
+				EmployeeNumber = 8051007,
+				Salary = 1_000_000,
+			};
+
+			employee.IsTransient.Should().BeTrue();
+		}
+
+		[Test]
+		public void ShouldReturnTrueForTransientEntityForNull()
+		{
+			Employee employee = new Employee
+			{
+				ID = null,
+				Name = "James Bond",
+				EmployeeNumber = 8051007,
+				Salary = 1_000_000,
+			};
+
+			employee.IsTransient.Should().BeTrue();
+		}
+
+		[Test]
+		public void ShouldReturnTrueForTransientEntityForOnlyWhitespace()
+		{
+			Employee employee = new Employee
+			{
+				ID = "     ",
+				Name = "James Bond",
+				EmployeeNumber = 8051007,
+				Salary = 1_000_000,
+			};
+
+			employee.IsTransient.Should().BeTrue();
+		}
+	}
+}