diff --git a/asgiref/compatibility.py b/asgiref/compatibility.py
index eccaee0d..3a2a63e6 100644
--- a/asgiref/compatibility.py
+++ b/asgiref/compatibility.py
@@ -1,6 +1,7 @@
-import asyncio
 import inspect
 
+from .sync import iscoroutinefunction
+
 
 def is_double_callable(application):
     """
@@ -18,10 +19,10 @@ def is_double_callable(application):
     if hasattr(application, "__call__"):
         # We only check to see if its __call__ is a coroutine function -
         # if it's not, it still might be a coroutine function itself.
-        if asyncio.iscoroutinefunction(application.__call__):
+        if iscoroutinefunction(application.__call__):
             return False
     # Non-classes we just check directly
-    return not asyncio.iscoroutinefunction(application)
+    return not iscoroutinefunction(application)
 
 
 def double_to_single_callable(application):
diff --git a/asgiref/sync.py b/asgiref/sync.py
index e0c10704..9b5a959f 100644
--- a/asgiref/sync.py
+++ b/asgiref/sync.py
@@ -378,7 +378,7 @@ def __init__(
         self.func = func
         functools.update_wrapper(self, func)
         self._thread_sensitive = thread_sensitive
-        self._is_coroutine = asyncio.coroutines._is_coroutine  # type: ignore
+        markcoroutinefunction(self)
         if thread_sensitive and executor is not None:
             raise TypeError("executor must not be set when thread_sensitive is True")
         self._executor = executor
diff --git a/tests/test_sync.py b/tests/test_sync.py
index 022a1743..15640e65 100644
--- a/tests/test_sync.py
+++ b/tests/test_sync.py
@@ -10,7 +10,7 @@
 
 import pytest
 
-from asgiref.sync import ThreadSensitiveContext, async_to_sync, sync_to_async
+from asgiref.sync import ThreadSensitiveContext, async_to_sync, sync_to_async, iscoroutinefunction
 from asgiref.timeout import timeout
 
 
@@ -645,8 +645,8 @@ def test_sync_to_async_detected_as_coroutinefunction():
     def sync_func():
         return
 
-    assert not asyncio.iscoroutinefunction(sync_to_async)
-    assert asyncio.iscoroutinefunction(sync_to_async(sync_func))
+    assert not iscoroutinefunction(sync_to_async)
+    assert iscoroutinefunction(sync_to_async(sync_func))
 
 
 async def async_process(queue):