The color of the patch should be close to yellow.
If the color is close to pink, it’s probably because a little presence of red cells or haemolysis fenomenon for a wrong blood collect or the clinical status of the patient. This not compromise the result and the patch can be applied.
If the color of the pach is deep red, probably during the pumping phase from the bag to the tube, red cells are passed. In this case too the patch can be applied, but a high presence of red cells in the patch could cause an high inflammatory response.