diff --git a/health/grpc_health_v1alpha/health.pb.go b/health/grpc_health_v1alpha/health.pb.go
index 14356f27..6bfbe497 100644
--- a/health/grpc_health_v1alpha/health.pb.go
+++ b/health/grpc_health_v1alpha/health.pb.go
@@ -21,10 +21,6 @@ import (
 	grpc "google.golang.org/grpc"
 )
 
-// Reference imports to suppress errors if they are not otherwise used.
-var _ context.Context
-var _ grpc.ClientConn
-
 // Reference imports to suppress errors if they are not otherwise used.
 var _ = proto.Marshal
 
@@ -52,7 +48,6 @@ func (x HealthCheckResponse_ServingStatus) String() string {
 }
 
 type HealthCheckRequest struct {
-	Host    string `protobuf:"bytes,1,opt,name=host" json:"host,omitempty"`
 	Service string `protobuf:"bytes,2,opt,name=service" json:"service,omitempty"`
 }
 
@@ -72,6 +67,10 @@ func init() {
 	proto.RegisterEnum("grpc.health.v1alpha.HealthCheckResponse_ServingStatus", HealthCheckResponse_ServingStatus_name, HealthCheckResponse_ServingStatus_value)
 }
 
+// Reference imports to suppress errors if they are not otherwise used.
+var _ context.Context
+var _ grpc.ClientConn
+
 // Client API for HealthCheck service
 
 type HealthCheckClient interface {
diff --git a/health/grpc_health_v1alpha/health.proto b/health/grpc_health_v1alpha/health.proto
index 747a4f03..1ca5bbc1 100644
--- a/health/grpc_health_v1alpha/health.proto
+++ b/health/grpc_health_v1alpha/health.proto
@@ -3,7 +3,6 @@ syntax = "proto3";
 package grpc.health.v1alpha;
 
 message HealthCheckRequest {
-  string host = 1;
   string service = 2;
 }
 
diff --git a/health/health.go b/health/health.go
index e7b63853..3a836f2a 100644
--- a/health/health.go
+++ b/health/health.go
@@ -24,7 +24,7 @@ func NewHealthServer() *HealthServer {
 }
 
 func (s *HealthServer) Check(ctx context.Context, in *healthpb.HealthCheckRequest) (*healthpb.HealthCheckResponse, error) {
-	service := in.Host + ":" + in.Service
+	service := in.Service
 	s.mu.Lock()
 	defer s.mu.Unlock()
 	if status, ok := s.statusMap[service]; ok {
@@ -37,8 +37,7 @@ func (s *HealthServer) Check(ctx context.Context, in *healthpb.HealthCheckReques
 
 // SetServingStatus is called when need to reset the serving status of a service
 // or insert a new service entry into the statusMap.
-func (s *HealthServer) SetServingStatus(host string, service string, status healthpb.HealthCheckResponse_ServingStatus) {
-	service = host + ":" + service
+func (s *HealthServer) SetServingStatus(service string, status healthpb.HealthCheckResponse_ServingStatus) {
 	s.mu.Lock()
 	s.statusMap[service] = status
 	s.mu.Unlock()
diff --git a/test/end2end_test.go b/test/end2end_test.go
index 761f25a1..1c9cc460 100644
--- a/test/end2end_test.go
+++ b/test/end2end_test.go
@@ -392,7 +392,6 @@ func healthCheck(t time.Duration, cc *grpc.ClientConn, serviceName string) (*hea
 	ctx, _ := context.WithTimeout(context.Background(), t)
 	hc := healthpb.NewHealthCheckClient(cc)
 	req := &healthpb.HealthCheckRequest{
-		Host:    "",
 		Service: serviceName,
 	}
 	return hc.Check(ctx, req)
@@ -406,7 +405,7 @@ func TestHealthCheckOnSuccess(t *testing.T) {
 
 func testHealthCheckOnSuccess(t *testing.T, e env) {
 	hs := health.NewHealthServer()
-	hs.SetServingStatus("", "grpc.health.v1alpha.HealthCheck", 1)
+	hs.SetServingStatus("grpc.health.v1alpha.HealthCheck", 1)
 	s, cc := setUp(hs, math.MaxUint32, "", e)
 	defer tearDown(s, cc)
 	if _, err := healthCheck(1*time.Second, cc, "grpc.health.v1alpha.HealthCheck"); err != nil {
@@ -422,7 +421,7 @@ func TestHealthCheckOnFailure(t *testing.T) {
 
 func testHealthCheckOnFailure(t *testing.T, e env) {
 	hs := health.NewHealthServer()
-	hs.SetServingStatus("", "grpc.health.v1alpha.HealthCheck", 1)
+	hs.SetServingStatus("grpc.health.v1alpha.HealthCheck", 1)
 	s, cc := setUp(hs, math.MaxUint32, "", e)
 	defer tearDown(s, cc)
 	if _, err := healthCheck(0*time.Second, cc, "grpc.health.v1alpha.HealthCheck"); err != grpc.Errorf(codes.DeadlineExceeded, "context deadline exceeded") {
@@ -457,7 +456,7 @@ func testHealthCheckServingStatus(t *testing.T, e env) {
 	if _, err := healthCheck(1*time.Second, cc, "grpc.health.v1alpha.HealthCheck"); err != grpc.Errorf(codes.NotFound, "unknown service") {
 		t.Fatalf("HealthCheck/Check(_, _) = _, %v, want _, error code %d", err, codes.NotFound)
 	}
-	hs.SetServingStatus("", "grpc.health.v1alpha.HealthCheck", healthpb.HealthCheckResponse_SERVING)
+	hs.SetServingStatus("grpc.health.v1alpha.HealthCheck", healthpb.HealthCheckResponse_SERVING)
 	out, err := healthCheck(1*time.Second, cc, "grpc.health.v1alpha.HealthCheck")
 	if err != nil {
 		t.Fatalf("HealthCheck/Check(_, _) = _, %v, want _, <nil>", err)
@@ -465,7 +464,7 @@ func testHealthCheckServingStatus(t *testing.T, e env) {
 	if out.Status != healthpb.HealthCheckResponse_SERVING {
 		t.Fatalf("Got the serving status %v, want SERVING", out.Status)
 	}
-	hs.SetServingStatus("", "grpc.health.v1alpha.HealthCheck", healthpb.HealthCheckResponse_NOT_SERVING)
+	hs.SetServingStatus("grpc.health.v1alpha.HealthCheck", healthpb.HealthCheckResponse_NOT_SERVING)
 	out, err = healthCheck(1*time.Second, cc, "grpc.health.v1alpha.HealthCheck")
 	if err != nil {
 		t.Fatalf("HealthCheck/Check(_, _) = _, %v, want _, <nil>", err)