There are a few reasons why your blood test results may be pending. The most common reason is that the laboratory is still waiting for results from another test that has been ordered to complete the picture. For example, a CBC (complete blood count) may be ordered to check for anemia. The lab may also need to perform a differential to see what type of cells are low. If the anemia is due to a low red blood cell count, the lab will also check for a high white blood cell count or a high platelet count, which may indicate leukemia. Another common reason for pending test results is that the lab is waiting for results from a confirmatory test. For example, a positive result for the hepatitis B surface antigen may be confirmed with a test for the hepatitis B e antigen.