Coombs' test involves taking a blood sample which is checked for the presence of antibodies which may destroy red blood cells.
You can use the HP Print and Scan Doctor to test the status of the printer spooler, print queue, device manager, and device conflicts. 1  On the desktop, double-click the HP Print and Scan Doctor icon to open the tool. 2  Click Start on the Welcome screen. 3  Select your printer, and then click Next.  Click Fix Printing.
On the Dock, click the HP Utility icon. Click Finder, click Applications, double-click the HP folder, and then double-click HP Utility. Under Scan Settings, click Scan to Computer. Select the Scan Tasks tab, select the task you want to modify, and then click Edit.