What diagnosis code?

A client sent me this question--can someone help?

Dr XX has asked me to send you an email.
Question: When a diagnosis is written for cholesterol or a varicella titer we are not knowing the results before hand, so we use “screening”, insurance companies are denying charges. What would be the proper diagnosis to write instead of “screening”? A hospital billing manager suggests “screening for disease” …any thoughts?

Why we need nationalized health insurance

Insurance companies get to make their own rules and the insurers sign a contract agreeing to abide by the rules. If the insurer does not pay for preventative care (V codes in general) then if the patient wants the service, they pay for it. If they want a cholesterol test just to see their number, it is screening. If they are in the office with chest pain, I will link the cholesterol to the 786.50 since it is part of my workup.
Likewise with varicella. If they have a rash, link it to the code for chicken pox; if it is screening to see if they are immune, the patient may have to pay.

Of course to complicate things some insurers pay GREAT for preventative care so if you code the test linked to a problem visit, the patient gets upset since it now applies to their deductible.