Oncology & Hematology Coding Alert

Watch out: Only code once for identical ports

Code 77300 often merits multiple units, but not every basic radiation dosimetry calculation qualifies. 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 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, an independent oncology coding consultant based in New Orleans.

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. If your payer is one of the few who doesn't want you to report calculations using the units box, you may be able to use a modifier, she adds.

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 two in the units box.

Verify Order and Medical Necessity

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

Your documentation also has to prove medical necessity. For you to code any calculation, your documentation must 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. Examples include off-axis calculations 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: 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, according to its North Carolina radiation oncology policy, available 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: Your report shows a prostate cancer patient with 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.

The "mirror image" calculations generally occur on palliative patients. For example, a patient has a recurrence of a lung tumor and the physician prescribes several fractions of palliative radiation to shrink the tumor and help the patient breathe more comfortably. You may have a single calculation for the AP/PA therapy.

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 a calculation separate from the IMRT calculations. "The monitor units (MUs) generated by the IMRT treatment plan must be independently checked before the patient's first treatment," according to some Medicare LCDs.

You can't report the IMRT calculations separately, but you can report the basic dosimetry code for each portal used in IMRT if your documentation shows separate corresponding calculations for each unit, Coleman says.