diff --git a/metrics.go b/metrics.go
index 8ef1058..f103c61 100644
--- a/metrics.go
+++ b/metrics.go
@@ -28,14 +28,6 @@ type namedMetric struct {
 	isAux  bool
 }
 
-func (nm *namedMetric) family() string {
-	n := strings.IndexByte(nm.name, '{')
-	if n < 0 {
-		return nm.name
-	}
-	return nm.name[:n]
-}
-
 type metric interface {
 	marshalTo(prefix string, w io.Writer)
 	metricType() string
@@ -306,3 +298,20 @@ func writeMetricFloat64(w io.Writer, metricName, metricType string, value float6
 	writeMetadataIfNeeded(w, metricName, metricType)
 	fmt.Fprintf(w, "%s %g\n", metricName, value)
 }
+
+func writeMetadataIfNeeded(w io.Writer, metricName, metricType string) {
+	if !isMetadataEnabled() {
+		return
+	}
+	metricFamily := getMetricFamily(metricName)
+	fmt.Fprintf(w, "# HELP %s\n", metricFamily)
+	fmt.Fprintf(w, "# TYPE %s %s\n", metricFamily, metricType)
+}
+
+func getMetricFamily(metricName string) string {
+	n := strings.IndexByte(metricName, '{')
+	if n < 0 {
+		return metricName
+	}
+	return metricName[:n]
+}
diff --git a/set.go b/set.go
index 338e2c0..3ad6073 100644
--- a/set.go
+++ b/set.go
@@ -49,11 +49,11 @@ func (s *Set) WritePrometheus(w io.Writer) {
 
 	prevMetricFamily := ""
 	for _, nm := range sa {
-		metricFamily := nm.family()
+		metricFamily := getMetricFamily(nm.name)
 		if metricFamily != prevMetricFamily {
 			// write meta info only once per metric family
 			metricType := nm.metric.metricType()
-			writeMetadataIfNeeded(&bb, metricFamily, metricType)
+			writeMetadataIfNeeded(&bb, nm.name, metricType)
 			prevMetricFamily = metricFamily
 		}
 		// Call marshalTo without the global lock, since certain metric types such as Gauge
@@ -63,14 +63,6 @@ func (s *Set) WritePrometheus(w io.Writer) {
 	w.Write(bb.Bytes())
 }
 
-func writeMetadataIfNeeded(w io.Writer, metricFamily, metricType string) {
-	if !isMetadataEnabled() {
-		return
-	}
-	fmt.Fprintf(w, "# HELP %s\n", metricFamily)
-	fmt.Fprintf(w, "# TYPE %s %s\n", metricFamily, metricType)
-}
-
 // NewHistogram creates and returns new histogram in s with the given name.
 //
 // name must be valid Prometheus-compatible metric with possible labels.