Question: A child presented with an NLD obstruction in her left eye. However, my ophthalmologist documented probing both eyes. How should I code for this?
Answer: Coding the procedure won't be as difficult as you might expect once you eliminate any inclinations to code for the probing of both nasolacrimal ducts (NLDs). The physician's motivation to probe both ducts is not expressed by the diagnosis of an obstruction in one eye. If there is only one diagnosis of a nasolacrimal duct obstruction (375.55, Obstruction of nasolacrimal duct, neonatal; 375.56, Stenosis of nasolacrimal duct, acquired; or 743.65, Specified congenital anomalies of lacrimal passages), the probing of the second eye may be considered not medically necessary by the patient's insurance.
In this case, if there was not a finding or diagnosis documented to substantiate the medical necessity for probing the right eye, you would append the left eye modifier, -LT, and bill only one eye, with the most accurate of the codes for nasolacrimal duct probe:
The other option is to bill the right eye with whatever diagnosis was documented that day, receive a denial, and bill the patient for the procedure.