A test strip with selective white blood cell (WBC) lysis for release of WBC contents and the capture and holding of red blood cells (RBC), allowing for fast clearance and result interpretation and more accurate results at early time points due to the lack of red color interference caused by background red heme color of lysing of RBCs. The removal of the red color interference enhances both visual and digital interpretation of test strips, such as test strips of an immunoassay test. The test strip enhances the detection of both intracellular proteins of WBCs and extracellular proteins of RBCs simultaneously such as MxA and CRP, MxA and PCT, MxA and HNL, and MxA and IL-6, MxA and myeloid cells (STREM-1), MxA and angiopoietin 2, MxA and vascular endothelial growth factor (VEGF) or its soluble vascular endothelial growth factor receptor-1 (sVEGFR1), MxA and heparin binding protein (HBP) or other combinations.