diff --git a/tests/test_files/test.xlsx b/tests/test_files/test.xlsx
index 56ec497..0dcbeb9 100755
Binary files a/tests/test_files/test.xlsx and b/tests/test_files/test.xlsx differ
diff --git a/tests/test_markitdown.py b/tests/test_markitdown.py
index edbeefe..76b4a02 100644
--- a/tests/test_markitdown.py
+++ b/tests/test_markitdown.py
@@ -126,6 +126,7 @@ def test_markitdown_local() -> None:
         assert test_string in text_content
     # Check negations
     assert "Unnamed:" not in text_content
+    assert "NaN" not in text_content
 
     # Test DOCX processing
     result = markitdown.convert(os.path.join(TEST_FILES_DIR, "test.docx"))