Fixed test and added whatsnew entry

doc/source/whatsnew/v1.0.0.rst

@@ -336,6 +336,7 @@ Numeric
 - Improved error message when using `frac` > 1 and `replace` = False (:issue:`27451`)
 - Bug in numeric indexes resulted in it being possible to instantiate an :class:`Int64Index`, :class:`UInt64Index`, or :class:`Float64Index` with an invalid dtype (e.g. datetime-like) (:issue:`29539`)
 - Bug in :class:`UInt64Index` precision loss while constructing from a list with values in the ``np.uint64`` range (:issue:`29526`)
+- Bug in :meth:`NumericIndex._convert_arr_indexer` that caused indexing to fail when integers in the ``np.uint64`` range were used (:issue:`28023`)
 -
 
 Conversion

pandas/tests/indexes/test_numeric.py

@@ -1205,4 +1205,4 @@ def test_uint_index_does_not_convert_to_float64():
     result = series.loc[[7606741985629028552, 17876870360202815256]].index
     expected = UInt64Index([7606741985629028552, 17876870360202815256], dtype="uint64")
 
-    assert tm.assert_index_equal(result, expected)
+    tm.assert_index_equal(result, expected)