diff --git a/lib/counter.js b/lib/counter.js
index 39a7bd1b..8ca56208 100644
--- a/lib/counter.js
+++ b/lib/counter.js
@@ -109,7 +109,7 @@ class Counter extends Metric {
 	async get() {
 		if (this.collect) {
 			const v = this.collect();
-			if (v instanceof Promise) await v;
+			if ((v instanceof Promise) || (v.then instanceof Function)) await v;
 		}
 
 		return {
diff --git a/lib/gauge.js b/lib/gauge.js
index 3725bf01..e1134f26 100644
--- a/lib/gauge.js
+++ b/lib/gauge.js
@@ -108,7 +108,7 @@ class Gauge extends Metric {
 	async get() {
 		if (this.collect) {
 			const v = this.collect();
-			if (v instanceof Promise) await v;
+			if ((v instanceof Promise) || (v.then instanceof Function)) await v;
 		}
 		return {
 			help: this.help,
diff --git a/lib/histogram.js b/lib/histogram.js
index 539620c2..fda2fc9e 100644
--- a/lib/histogram.js
+++ b/lib/histogram.js
@@ -108,7 +108,7 @@ class Histogram extends Metric {
 	async getForPromString() {
 		if (this.collect) {
 			const v = this.collect();
-			if (v instanceof Promise) await v;
+			if ((v instanceof Promise) || (v.then instanceof Function)) await v;
 		}
 		const data = Object.values(this.hashMap);
 		const values = data
diff --git a/lib/summary.js b/lib/summary.js
index 28fdb07a..9db8d2c4 100644
--- a/lib/summary.js
+++ b/lib/summary.js
@@ -51,7 +51,7 @@ class Summary extends Metric {
 	async get() {
 		if (this.collect) {
 			const v = this.collect();
-			if (v instanceof Promise) await v;
+			if ((v instanceof Promise) || (v.then instanceof Function)) await v;
 		}
 		const hashKeys = Object.keys(this.hashMap);
 		const values = [];