diff --git a/test/parallel/test-readfloat.js b/test/parallel/test-readfloat.js
index 0175c195b8ec22..79e0d5a044f936 100644
--- a/test/parallel/test-readfloat.js
+++ b/test/parallel/test-readfloat.js
@@ -29,7 +29,7 @@ function test(clazz) {
   buffer[1] = 0xff;
   buffer[2] = 0x7f;
   buffer[3] = 0x7f;
-  assert.ok(isNaN(buffer.readFloatBE(0)));
+  assert.ok(Number.isNaN(buffer.readFloatBE(0)));
   assert.strictEqual(3.4028234663852886e+38, buffer.readFloatLE(0));
 
   buffer[0] = 0xab;