Radiology Coding Alert

Put the 'basic' back in your basic dosimetry coding

Not every port requiring basic radiation dosimetry calculation qualifies for code 77300. Our coding experts give you the dosimetry lowdown to speed up reimbursement and put a stop to denials.

Ask About Per-Port Payment

Many payers will only pay once per port per treatment setup when it comes to CPT 77300 (Basic radiation dosimetry calculation, central axis depth dose calculation, TDF, NSD, gap calculation, off-axis factor, tissue inhomogeneity factors, calculation of non-ionizing radiation surface and depth dose, as required during course of treatment, only when prescribed by the treating physician), says Margaret Hickey, MS, MSN, RN, OCN, CORLN, a New Orleans-based oncology coding consultant.

If this is the case for your payer, count the number of ports the dosimetrist provides calculations for and report 77300 with the appropriate number in the units box, says Deborah Esposito, CPC, a radiation oncology coder for Thomas O'Connor, MD, in West Seneca, N.Y.

Example: Your radiation oncologist orders monitor units for breast tangents for a patient with breast cancer, resulting in two dosimetry calculations - one for each tangent or portal. You should report 77300 with "2" in the units box.

Verify Order and Medical Necessity

Other payers may be willing to reimburse you for every calculation performed, but you still need the proper documentation, Esposito says.

Example: For you to code a second calculation of the same port, your documentation should clearly reflect the changes requiring additional dosimetry charges, such as a note by the radiation oncologist, says Tamara Abraham, CPC, a North Carolina coder specializing in radiation oncology. Plus: The dosimetrist should sign off on "a template in the chart that reflects the date(s) and different planning stages for dosimetry billing and services," Abraham says.

Opportunity: You may code dosimetry at any time during the course of radiation therapy when documentation shows a medically necessary calculation, Esposito says. Especially at the beginning of treatment, you may see a number of situations that need individual radiation dosage point calculations, she adds, such as off-axis and gap calculations.

Stay Alert for Changing Conditions

Payers typically reimburse you for additional calculations if the patient's situation alters, such as when the tumor volume changes, Esposito says.

Example: Your patient has five ports requiring calculation, so you report 77300 with 5 units. If the patient receives radiation therapy, shrinking the tumor, the dosimetrist must create new calculations to determine the location of the tumor and the dosage amount, Abraham says. At this time, you may report additional units for the additional calculations.

Tip: See if your payer, like Cigna Medicare, will pay for a new set of calculations even when the change in condition is a patient's change in weight or girth. You can see Cigna's North Carolina radiation oncology policy for the details at www.cignamedicare.com/partb/lmrp/nc/cms_fu/2001-002-001.htm.

Don't Code Mirror-Image

The major exception to the calculation-reporting rule is: Only report one unit for multiple ports that are identical in size, shape and depth, Esposito says.
 
Example 1: A prostate cancer patient has two sets of opposed ports - anterior/posterior ports with one set of measurements and left/right with another. Even though you have four ports, you only have two calculations, so you should report 77300 twice.

Example 2: A patient has a recurrence of a lung tumor. The physician prescribes several fractions of palliative radiation to shrink the tumor and help the patient breathe more comfortably. You have one calculation for the AP/PA therapy, so report 77300 once.

Another exception: If your report shows the dosimetrist performed a second calculation to correct an error he made in the first, only code for one calculation,  Esposito says

Avoid Bundling 77300 Into 77301

For a brief time, the National Correct Coding Initiative (NCCI) told insurers not to pay for 77300 when performed on the same date of service as 77301 (Intensity modulated radiotherapy plan, including dose-volume histograms for target and critical structure partial tolerance specifications), says Ramona Coleman, CPC, a radiation oncology coder in Aurora, Ill. NCCI deleted this edit retroactively, she adds.

Snag: To report 77300 with 77301, you need to perform and document separate calculations, independently checking each IMRT calculation, which many doctors use special software for.

How to do it: You can't report the IMRT calculations individually, but you can report the basic dosimetry code for each portal used in IMRT if your documentation shows separate corresponding calculations for each unit.