Hi
Your physician should list why the patient is needing these lab tests. Medical coders should not guess, but does he or she your provider mention patient needs further testing for certain disease or abnormalities documented for the treatment on a day before get labs ? To get payment and have clear supporting documentation for ordering such lab test need dx justification. Some encoders can guide you when listing the CPT lab code in selecting dx codes, but must be in coordination with the patient's health. I do know if the patient has never had the disease and the doc is checking you can use the proper Z encounter dx code, but this usually should be the 2nd dx code on the claim. The lab and insurance company would like a disease code related to the reason for blood, urine, or biopsy specimen gathered. Also check the ongoing chronic conditions(ie DM, HTN, CHKD, COPD) the patient has which my help.
See below some lab test used in past per my provider's documentation but mind you many lipid and STD lab test per CPT manual.
Fecal CPT 82270 use dx R19.8 and Z13.811 or K92 or K92.1
PSA Prostate CPT 84157 use dx N42.9 and Z13.89
STD bacteria test CPT 87491 used dx A63.8 and Z11.3
Well hope this helps you a little bit
Lady T