Pennsylvania Subscriber
Answer: You are correct to bill only once for the test over two days, and because you're using a code for "multiple studies," you may only be allowed to code once even if the patient doesn't return for two months. Single- phase codes may be more appropriate.
For the stress test, you use 93015 (Cardiovascular stress test using maximal or submaximal treadmill or bicycle exercise, continuous electrocardiographic monitoring, and/or pharmacological stress; with physician supervision, with interpretation and report). Or, if it's more appropriate, choose 93016 (... physician supervision only, without interpretation and report), 93017 (... tracing only, without interpretation and report), or 93018 (... interpretation and report only).
Your question involves 78465 (Myocardial perfusion imaging; tomographic [SPECT], multiple studies, at rest and/or stress [exercise and/or pharmacologic] and redistribution and/or rest injection, with or without quantification) or 78461 (... multiple studies, [planar] at rest and/or stress [exercise and/or pharmacologic] and redistribution and/or rest injection, with or without quantification). You'll notice that the descriptors indicate that 78465 and 78461 are for multiple studies. You absolutely should not report either of these codes twice for a two-day protocol.
This means that if you report add-on codes +78478 (Myocardial perfusion study with wall motion, qualitative or quantitative study) or +78480 (Myocardial perfusion study with ejection fraction), you only report them once, with 78465.
Try this: If a patient doesn't return for a month or two for the second part of the test, check with your payer for what they think is proper. A one-month hiatus between tests is clinically inappropriate for multi-phase cardiac testing, so single-phase codes are the more likely choice. Choose 78460 (... [planar] single study, at rest or stress [exercise and/or pharmacologic] with or without quantification) or 78464 (... tomographic [SPECT], single study at rest or stress [exercise and/or pharmacologic] with or without quantification).
Your doctor will probably provide two separate reports, so you can bill the appropriate single studies based on the documentation. For instance, the documentation may indicate 78460 (Myocardial perfusion imaging; [planar] single study, at rest or stress [exercise and/or pharmacologic], with or without quantification) or 78464 (... tomographic [SPECT], single study at rest or stress [exercise and/or pharmacologic], with or without quantification). But you should bill a multiple-studies code only once.