diff --git a/tests/xtimer_usleep/README.md b/tests/xtimer_usleep/README.md
index 6f91697c1e..d387d9ed99 100644
--- a/tests/xtimer_usleep/README.md
+++ b/tests/xtimer_usleep/README.md
@@ -84,3 +84,20 @@ Invalid timeout 1464 ,expected 1172 < 1234 < 1295
 Host max error  61
 error           291
 ```
+
+Test also fails with negative offset as xtimer_usleep must sleep for at least
+the expected time.
+
+```
+XXXX-XX-XX XX:XX:XX,XXX - INFO # Connect to serial port /dev/ttyACM0
+Welcome to pyterm!
+Type '/exit' to exit.
+XXXX-XX-XX XX:XX:XX,XXX - INFO # main(): This is RIOT! (XXX)
+XXXX-XX-XX XX:XX:XX,XXX - INFO # Running test 5 times with 7 distinct sleep times
+XXXX-XX-XX XX:XX:XX,XXX - INFO # Please hit any key and then ENTER to continue
+a
+XXXX-XX-XX XX:XX:XX,XXX - INFO # Slept for 9979 us (expected: 10000 us) Offset: -21 us
+Invalid timeout 9979 ,expected 10000 < 10500
+Host max error  500
+error           -21
+```
\ No newline at end of file
diff --git a/tests/xtimer_usleep/tests/01-run.py b/tests/xtimer_usleep/tests/01-run.py
index 983bfcc89c..3766be750a 100755
--- a/tests/xtimer_usleep/tests/01-run.py
+++ b/tests/xtimer_usleep/tests/01-run.py
@@ -33,17 +33,17 @@ def testfunc(child):
         start_test = time.time()
         for m in range(RUNS):
             for n in range(SLEEP_TIMES_NUMOF):
-                child.expect(u"Slept for (\\d+) us \\(expected: (\\d+) us\\) Offset: (\\d+) us")
+                child.expect(u"Slept for (\\d+) us \\(expected: (\\d+) us\\) Offset: (-?\\d+) us")
                 sleep_time = int(child.match.group(1))
                 exp = int(child.match.group(2))
-                lower_bound = exp - (exp * INTERNAL_JITTER)
                 upper_bound = exp + (exp * INTERNAL_JITTER)
-                if not (lower_bound < sleep_time < upper_bound):
-                    delta = (upper_bound-lower_bound)/2
-                    raise InvalidTimeout("Invalid timeout %d ,expected %d < %d < %d"
+                if not (exp < sleep_time < upper_bound):
+                    delta = (upper_bound-exp)
+                    error = min(upper_bound-sleep_time, sleep_time-exp)
+                    raise InvalidTimeout("Invalid timeout %d, expected %d < timeout < %d"
                                          "\nHost max error\t%d\nerror\t\t%d" %
-                                         (sleep_time, lower_bound, exp, upper_bound,
-                                          delta, sleep_time-lower_bound))
+                                         (sleep_time, exp, upper_bound,
+                                          delta, error))
         testtime = (time.time() - start_test) * US_PER_SEC
         child.expect(u"Test ran for (\\d+) us")
         exp = int(child.match.group(1))