Dermatology Coding Alert

Understand the difference between scratch tests and patch tests to maximize coding accuracy.

Keeping track of all the different potential allergens that may be causing a patient's skin rash is challenging enough. But when you add the complexity of the several different kinds of dermatitis tests that a dermatologist can perform, it's enough to cause a coder to break out in a rash herself. The variety and complexity of allergy tests can certainly lead to coding mishaps -- but understanding the codes and having clear documentation can help clear things up.

The tests that dermatologists commonly perform to learn the source of a patient's allergic dermatitis include scratch tests and patch tests. Knowing what code to use means understanding what each test does, and how.

Count Each Allergen in Scratch Tests

Procedure: Percutaneous tests

AKA: Scratch tests, prick tests, puncture tests, Multi-Test

Codes: 95004 (Percutaneous tests [scratch, puncture, prick] with allergenic extracts, immediate type reaction, including test interpretation and report by a physician, specify number of tests) and 95010 (Percutaneous tests [scratch, puncture, prick] sequential and incremental, with drugs, biologicals or venoms, immediate type reaction, including test interpretation and report by a physician, specify number of tests).

Watch for: In these tests, the dermatologist applies test solutions of possible allergens to scratches or shallow punctures of the skin. The code you report will depend on the type of solutions applied -- allergenic extracts, such as dust, cat dander, and molds (95004), or antibiotics, biologicals, stinging insects, and local anesthetic agents (95010).

Dermatologists usually want to test several substances at once (often in blocks of eight), and each substance counts as a separate test, notes Pamela Biffle, CPC, CPC-P, CPC-I, CCSP, CHCC, CHCO, owner of PB Healthcare Consulting and Education Inc. in Watauga, Texas. Be sure to code for each allergen administered by putting the number in the "units" field of your claim form.

Hidden trap: Code each allergen, not each scratch.

Even if the dermatologist has to perform multiple scratches for one allergen, that allergen counts as one unit of service.

Example: A dermatologist tests a patient for reactions to dogs, cats, ragweed, oak, maple, penicillin, dust mites, and bees. You report 95004 x 4 units for the ragweed, oak, maple, and dust mites, and 95010 x 4 units for the dog, cat, penicillin, and bee stings.

Note: Intracutaneous tests, in which the physician injects the allergen into the skin, are often necessary when percutaneous tests are unclear. Report these tests with 95015-95028 (Intracutaneous [intradermal] tests ...).

Report one unit of service per allergen for 95015, 95024, and 95028; report each injection separately for 95027 (also known as the end-point titration test, used to find the highest dilution of a substance that causes a reaction in order to set a baseline for immunotherapy).

Check Documentation for E/M With Patch Tests

Procedure: Patch tests

AKA: Application tests, T.R.U.E. Tests

Code: 95044 (Patch or application test[s] [specify number of tests])

Watch for: 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.

First visit: As for the scratch tests, 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.

Append modifier 25 (Significant, separately identifiable evaluation and management service by the same physician 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.

Example: The dermatologist examines an established patient with a history of recurrent dermatitis. He performs an expanded problem focused examination of the affected areas, diagnoses unspecified contact dermatitis, and decides to apply a patch test with 24 possible allergens.

Report 99213-25 x 1 and 95044 x 24 for this initial visit, linked to ICD-9 code 692.9 (Contact dermatitis and other eczema; unspecified cause).

Exception: Don't report an E/M code with 95044 if the patient comes back later for the patch test. Example: During the first office visit, the dermatologist decides to apply a patch test. That day is inconvenient for the patient, however, so he returns the following week and a nurse applies the patch tests. Just report 95044 x 24 for the application.

Next visits: 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.

Example: After 48 hours, the dermatologist finds that natural rubber latex caused a strong positive reaction. During a 25- minute visit, he spends 15 minutes counseling the patient on avoiding the allergen. Report 99214 (Office or other outpatient visit for the evaluation and management of an established patient ...) x 1, linked to the new specific diagnosis (692.89, ... due to other specified agents).

Make Sure Carrier Recognizes Allergen

Most carriers will cover patch tests for patients with suspected contact dermatitis -- but only if the dermatitis is caused by certain allergens. Generally, carriers will accept ICD-9 codes 692.0-692.6, which include allergens such as detergents, drugs, food, and plants to prove medical necessity for patch testing. Diagnosis codes 692.81 (Dermatitis due to cosmetics), 692.83 (Dermatitis due to metals), and 692.89 are usually also acceptable.

Say cheese: A dermatologist might also perform a "photo patch test." In this test, the test area is exposed to ultraviolet light after 48 hours. If the test is positive, a more severe reaction develops at the patch site than on surrounding skin. Although this may sound like a combination of 95044 and 95056 (Photo tests), do not report both codes. Photo patch tests have their own CPT code, 95052 (Photo patch test[s] [specify number of tests]).