diff --git a/Include/longobject.h b/Include/longobject.h
index 7f2cda6..b7a29b5 100644
--- a/Include/longobject.h
+++ b/Include/longobject.h
@@ -11,7 +11,8 @@
 
 PyAPI_DATA(PyTypeObject) PyLong_Type;
 
-#define PyLong_Check(op) PyObject_TypeCheck(op, &PyLong_Type)
+#define PyLong_Check(op) \
+		PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_LONG_SUBCLASS)
 #define PyLong_CheckExact(op) ((op)->ob_type == &PyLong_Type)
 
 PyAPI_FUNC(PyObject *) PyLong_FromLong(long);