Oncology & Hematology Coding Alert

Question: I got a charge sheet with 77331 circled. The physician ordered special monitoring for a patient with a very small treatment area. Would coding 77331 in this instance be correct?

Virginia Subscriber

Answer: The described situation may meet the requirements for 77331 (Special dosimetry [e.g., TLD,microdosimetry] [specify], only when prescribed by the treating physician).

According to an American Society for Therapeutic Radiology and Oncology (ASTRO) -Coding FAQ,- -Use should be for special situations such as dose at abutting fields, unusually small fields, verifying dose under bolus, etc.- As the ASTRO FAQ stresses, most patients won't require special dosimetry, which measures radiation dose at a given point with specialized monitoring equipment (www.astro.org/HealthPolicy/RadiationOncologyCoding/CodingFAQ/Dosimetry/index.asp).

You should never use 77331 for routine quality assurance monitoring. This means you should not report this code for room surveys, patient surveys, or routine plan verification.

But if the radiation oncologist orders special radiation measuring and monitoring devices to determine the correct radiation dose at a given point and then uses the results to accept or modify the treatment plan, you-re on the right track for proper 77331 coding.

The monitoring devices may include thermoluminescent dosimeters (TLD), solid-state diode probes,special dosimetry probes, or film dosimetry. Documentation must indicate the type of special dosimetry.

The documentation also should describe the special radiation measuring and monitoring devices and all of the treatment fields that required special dosimetry. Both the doctor and physicist should sign a hard copy of the measurements, and you should have documentation prior to the measurement explaining how the special dosimetry will affect the patient's current treatment plan.

How often? Payers typically reimburse 77331 once per port per course of treatment when the service is medically necessary.