Check out http://www.anapsid.org/lyme/strickerpanel.html for more info on the CD-57 test. Perhaps supplying your doctor with a printout of this page would enable him to order the correct test.
Here is a link to the initial study about
the CD-57 test in relation to Chronic Lyme Disease:http://www.aaem.pl/pdf/aaem0217.pdf
There is no relation between total Lymphocyte count and CD-57 count. I happen to be low for all categories of Lymphocytes (total WBC count, total lymphocyte count, CD3, CD4, NK cells, and CD-57) but most on here aren't low on all of these.