Dermatology Coding Alert

Tip: Code for each allergen, not each scratch.

Could one of these skin allergy testing myths be keeping you scratching your head? Need to patch up your coding strategy? Read on.

Dermatologists have many ways to determine the cause of a patient’s troublesome skin rash. The variety and complexity of allergy tests can lead to coding mishaps – but understanding the codes and having clear documentation can be your map out of the coding labyrinth.

The tests that dermatologists commonly perform to learn the source of a patient’s allergic dermatitis include scratch tests (CPT® code 95004, Percutaneous tests [scratch, puncture, prick] with allergenic extracts, immediate type reaction, including test interpretation and report, specify number of tests) and patch tests (CPT® code 95044, Patch or application test[s] [specify number of tests]), says Pamela Biffle, CPC, CPC-P, CPC-I, CPCO, owner of PB Healthcare Consulting and Education Inc. in Austin, Texas. Knowing what code to use means understanding what each test does, and how.

Myth: When coding percutaneous skin allergy tests, code for each scratch.

Reality: You should code for each allergen, not each scratch – even if your dermatologist has to perform multiple scratches for each allergen.

In percutaneous tests, also known as scratch tests, prick tests, puncture tests or the Multi-Test, the dermatologist applies test solutions of possible allergens to scratches or shallow punctures of the skin. The CPT® code you report will be 95004.

Dermatologists usually want to test several substances at once (often in blocks of eight), and each substance counts as a separate test. Be sure to code for each allergen administered by putting the number in the “units” field of your claim form.

Example: A dermatologist tests a patient for reactions to ragweed, oak, maple, penicillin, dust mites, and bees. You report 95004 x 4 units for the ragweed, oak, maple, and dust mites; 95017 (Allergy testing, any combination of percutaneous [scratch, puncture, prick] and intracutaneous [intradermal], sequential and incremental, with venoms, immediate type reaction, including test interpretation and report, specify number of tests) x 1 unit for the bee sting; and 95018 (… with drugs or biologicals, immediate type reaction, including test interpretation and report, specify number of tests) x 1 unit for the penicillin.

Myth: You can’t code separately for the follow-up visit to get the results of a patch test.

Reality: For a patch (or application or T.R.U.E.) test, the CPT® code is 95044. You would report the units for the patch test in box 24g according to the number of allergens tested. Be sure the dermatologist has documented the number of patch tests he administered.

Also, code for the E/M services the dermatologist provides to the patient based on the scope of the examination and the key components the dermatologist covers with the patient over and above the testing, Biffle says.

Append modifier 25 (Significant, separately identifiable evaluation and management service by the same physician or other qualified health care professional on the same day of the procedure or other service) to your E/M code to notify the payer that the dermatologist performed an initial evaluation that led him to complete patch testing on this patient.

On the testing date of service, link the visit to ICD10 code L23.9 (Allergic contact dermatitis, unspecified cause) for the testing, says Biffle.

The patch test is not an “immediate type reaction” test like the percutaneous test. After the dermatologist applies the patch containing samples of allergens to the patient’s back, the patient must come back in 48 hours (and, in some cases, once more after 72 and/or 96 hours) so the dermatologist can see the patient’s reaction to the allergens.

For the follow-up visits to read the results of the patch test, report the appropriate E/M code. Often, once the test has narrowed down the offending allergens, the dermatologist will spend time with the patient discussing the diagnosis and counseling him on treatment options. If the dermatologist spends more than half of the total length of the visit counseling the patient, you can use time to determine the level of E/M code to report.

Don’t miss: If a nurse or physician assistant reads the patch tests, you should report 99211, as long as the dermatologist is on-site when the staff member reads the results. Based on these readings, the dermatologist is able to make a more definitive diagnosis, so you should report the cause of the dermatitis. For instance, you may report one of the following ICD-10 codes to describe the specific type of dermatitis:

• L23.0 – Allergic contact dermatitis due to metals
• L23.1 – ... adhesives
• L23.2 – ... cosmetics
• L23.3 –... drugs in contact with skin
• L23.4 –... dyes
• L23.5 –... other chemical products
• L23.6 –... food in contact with skin
• L23.7 –... plants, except food
• L23.81 –... animal (cat) (dog) dander
• L23.89 –... due to other agents
• L23.9 –... …unspecified cause.

Bottom line: On the reading date of service, you would report one of the above diagnosis codes – usually with only an E/M CPT® code, Biffle says.

Myth: You can only code once no matter how many patches the dermatologist applies.

Reality: When the dermatologist administers patch tests, he applies several patches on the patient to test for his reaction to various allergens. Therefore, think of each test as an individual procedure because carriers do, and you should bill accordingly.

Red flag: If the dermatologist places 24 patches on a patient, carriers will reimburse your practice for 24 tests, but you have to include this information on your claim because carriers will always underestimate the number of tests.

Hint: Bill your units in block 24G on your CMS-1500 form according to the number of allergens tested.

Extra: You can also take a few precautions, to avoid overlooking billing the units in the future:

• Educate staff to double-check charge tickets for units.
• Educate the dermatologist to document the number of correct units.
• Teach front-desk staff to ask the dermatologist how many patch tests he administered.
• Since most offices use patch tests kits that include a set number of tests per kit, add a place on your forms that automatically has the number of tests already on the sheet, according to how many tests are in the kit.