diff --git a/core/readpref/options.go b/core/readpref/options.go
index e428ff76ee..e7b8e9789a 100644
--- a/core/readpref/options.go
+++ b/core/readpref/options.go
@@ -34,14 +34,15 @@ func WithMaxStaleness(ms time.Duration) Option {
 // overrides all previous calls to either method.
 func WithTags(tags ...string) Option {
 	return func(rp *ReadPref) error {
-		if len(tags)%2 != 0 {
+		length := len(tags)
+		if length < 2 || length % 2 != 0 {
 			return ErrInvalidTagSet
 		}
 
-		tagset := make(tag.Set, 0)
+		tagset := make(tag.Set, 0, length/2)
 
-		for i := 0; i < len(tags)/2; i++ {
-			tagset = append(tagset, tag.Tag{Name: tags[i], Value: tags[i+1]})
+		for i := 1; i < length; i+=2 {
+			tagset = append(tagset, tag.Tag{Name: tags[i-1], Value: tags[i]})
 		}
 
 		return WithTagSets(tagset)(rp)
diff --git a/core/readpref/readpref_test.go b/core/readpref/readpref_test.go
index c62be25661..c9257f10ae 100644
--- a/core/readpref/readpref_test.go
+++ b/core/readpref/readpref_test.go
@@ -39,14 +39,14 @@ func TestPrimaryPreferred_with_options(t *testing.T) {
 	require := require.New(t)
 	subject := PrimaryPreferred(
 		WithMaxStaleness(time.Duration(10)),
-		WithTags("a", "1"),
+		WithTags("a", "1", "b", "2"),
 	)
 
 	require.Equal(PrimaryPreferredMode, subject.Mode())
 	ms, set := subject.MaxStaleness()
 	require.True(set)
 	require.Equal(time.Duration(10), ms)
-	require.Equal([]tag.Set{{tag.Tag{Name: "a", Value: "1"}}}, subject.TagSets())
+	require.Equal([]tag.Set{{tag.Tag{Name: "a", Value: "1"},tag.Tag{Name: "b", Value: "2"}}}, subject.TagSets())
 }
 
 func TestSecondaryPreferred(t *testing.T) {
@@ -63,14 +63,14 @@ func TestSecondaryPreferred_with_options(t *testing.T) {
 	require := require.New(t)
 	subject := SecondaryPreferred(
 		WithMaxStaleness(time.Duration(10)),
-		WithTags("a", "1"),
+		WithTags("a", "1", "b", "2"),
 	)
 
 	require.Equal(SecondaryPreferredMode, subject.Mode())
 	ms, set := subject.MaxStaleness()
 	require.True(set)
 	require.Equal(time.Duration(10), ms)
-	require.Equal([]tag.Set{{tag.Tag{Name: "a", Value: "1"}}}, subject.TagSets())
+	require.Equal([]tag.Set{{tag.Tag{Name: "a", Value: "1"},tag.Tag{Name: "b", Value: "2"}}}, subject.TagSets())
 }
 
 func TestSecondary(t *testing.T) {
@@ -87,14 +87,14 @@ func TestSecondary_with_options(t *testing.T) {
 	require := require.New(t)
 	subject := Secondary(
 		WithMaxStaleness(time.Duration(10)),
-		WithTags("a", "1"),
+		WithTags("a", "1", "b", "2"),
 	)
 
 	require.Equal(SecondaryMode, subject.Mode())
 	ms, set := subject.MaxStaleness()
 	require.True(set)
 	require.Equal(time.Duration(10), ms)
-	require.Equal([]tag.Set{{tag.Tag{Name: "a", Value: "1"}}}, subject.TagSets())
+	require.Equal([]tag.Set{{tag.Tag{Name: "a", Value: "1"},tag.Tag{Name: "b", Value: "2"}}}, subject.TagSets())
 }
 
 func TestNearest(t *testing.T) {
@@ -111,12 +111,12 @@ func TestNearest_with_options(t *testing.T) {
 	require := require.New(t)
 	subject := Nearest(
 		WithMaxStaleness(time.Duration(10)),
-		WithTags("a", "1"),
+		WithTags("a", "1", "b", "2"),
 	)
 
 	require.Equal(NearestMode, subject.Mode())
 	ms, set := subject.MaxStaleness()
 	require.True(set)
 	require.Equal(time.Duration(10), ms)
-	require.Equal([]tag.Set{{tag.Tag{Name: "a", Value: "1"}}}, subject.TagSets())
+	require.Equal([]tag.Set{{tag.Tag{Name: "a", Value: "1"},tag.Tag{Name: "b", Value: "2"}}}, subject.TagSets())
 }