Same-day biopsy. Same-day office visit. Two lines on one claim, and the second one gets bundled into the first unless the claim proves it deserves its own payment.
That single pattern is behind many of the denials dermatology practices face, and it’s just one of the traps. Dermatology is a tough speciality for medical billing because a ten-minute visit can produce an E/M code, two biopsies, a destruction code and a pathology claim in one sitting. Delaware adds three Medicaid health plans and a state prompt-pay rule, and Medicare has a proposal that could reduce your 2027 same-day revenue.
Claimstone Billing has more than 10 years of combined experience fixing these claims. This guide covers the Delaware rules, the codes that cause the most trouble and the payer requirements to check, so your claims go out clean and come back paid.
Why do dermatology claims break so often in Delaware?
“Look, dermatology is a volume game. “A busy provider can see 40 patients in a day, and many of those visits end up being a procedure. Each requires a diagnosis to support the procedure, a modifier to save the visit and a note to support them both.
Delaware has only three counties (New Castle, Kent and Sussex), but the payer mix is broad. “Medicare Part B is through Novitas Solutions. Medicaid is split between fee-for-service and managed care.” Highmark Blue Cross Blue Shield Delaware is the state’s blue plan. National carriers make up the commercial side, and out-of-state cards from Maryland and Pennsylvania patients follow other rules.
One slip ripples from the front desk. Eligibility is checked on the incorrect plan, and the claim is dead before the provider walks in.
Delaware Medicaid rules that decide whether you get paid
Start with the clock. Delaware’s Medicaid program (DMAP) wants initial claims within twelve months of the date of service, and its general policy manual spells out the exceptions. A claim held up by a primary carrier gets considered for up to six months after you receive that carrier’s decision. A paid claim can be adjusted for up to two years from the date of service.
Then, the order of billing is as follows. Medicaid pays last, so bill every other insurance first and verify eligibility on the date of service. If the patient sits in a managed care plan, that plan’s authorizations have to be in hand before the visit. Prior authorization requests go through the DMAP provider portal.
Documentation gets audited harder than most practices expect. The manual asks for a diagnosis consistent with the service billed, the date, the member’s name and Medicaid ID, the person who performed the service, and the nature, extent, units and place of service. A note that states “lesion removed” but does not include the site, size, or count will fail on sight.
Cosmetic work is a hard no. DMAP does not pay for procedures meant to improve appearance within the normal range or for drugs used for cosmetic purposes. If a patient wants a non-covered service anyway, you can bill them only if you told them before the service that DMAP won’t pay and you documented it. Telling them afterwards doesn’t count.
Delaware Medicaid benefits are largely provided through three plans: AmeriHealth Caritas, Delaware First Health and Highmark Health Options (see the state’s Diamond State Health Plan page for a list). Each plan has its list of authorisations and filing rules. So what worked for one plan may not work for the next. The manual even cautions against the one-page code cheat sheet that billers pass from one to another (section 1.20.1.5). Keep dated copies of each plan’s policies in a shared folder and review them every quarter.
Filing deadlines and prompt-pay rules for commercial and Medicare claims
Pursuant to Insurance Department Regulation 1310, commercial carriers in Delaware are required to respond to a clean claim within 30 days of receipt. Day 31 – Set a reminder. If the claim is still sitting, call and cite the statute. The word “clean” matters. A missing modifier or a misdiagnosed diagnosis can knock the claim out of that category. So everything below protects the 30-day clock as well as the payment.
Medicare Part B allows one calendar year from the date of service. Commercial deadlines live in each contract and are often shorter, sometimes much shorter. Check them before you assume you have a year.
The dermatology codes that cause the most trouble
Biopsies first. CPT 11102 through 11107 split by technique: tangential, punch and incisional, each with an add-on code for extra lesions. The code follows the technique and ignores lesion size. Take three samples from one lesion, and you bill one unit. Take one from each of three lesions, and you bill the primary code once plus the add-on twice.
Then comes destruction. For premalignant lesions such as actinic keratoses, 17000 is the first lesion, 17003 is lesions two through 14 (billed per lesion) and 17004 is 15 or more (billed once). Warts and other benign lesions are similarly divided: 17110 for up to 14 and 17111 for 15 or more. CPT 11200 and 11201 – Removal of skin tags Most payers consider this cosmetic unless the note indicates irritation or bleeding.
Excisions turn on size. The measurement is the lesion plus the narrowest margins, taken before closure. Pathology reports usually show a smaller number because tissue shrinks Once the lesion is removed, code it from the operative note. Benign excisions live in 11400 to 11446, and malignant ones in 11600 to 11646. Simple repair is bundled into the excision, while intermediate and complex repairs are billed separately.
Mohs has its own family, 17311 to 17315. Codes 17311 and 17312 cover the first and additional stages on the head, neck, hands, feet and genitalia. Codes 17313 and 17314 do the same for trunk, arms and legs, and 17315 covers each extra tissue block after the first five in a stage. The surgeon acts as a pathologist, so frozen-section codes don’t go on Mohs slides. The reconstruction afterwards is separate, with its code and its own documentation.
Pathology on routine skin biopsies usually bills under 88305. If your practice runs its own lab, you need the right CLIA certificate. If an outside lab reads the slides, that lab bills the claim, and a practice that bills it too has created a duplicate.
Modifier 25, modifier 57 and the 2027 proposal
Modifier 25 is applied to the E/M when a procedure with a zero- or ten-day global period occurs on the same day. The E/M must be significant and separately identifiable because the decision to perform the biopsy is already included in the payment for the biopsy. A new rash, a second complaint, and a full skin check that turns up the lesion? That earns the 25. “Patient came in for biopsy; biopsy done” doesn’t.
If the procedure has a 90-day global (a flap or a graft), the decision-to-operate visit instead takes modifier 57.
The same day, different lesions are treated differently. Biopsy one and destroy another, and you usually need a separate procedure modifier (XS or 59, depending on the payer’s wishes). Same lesion? Same time? It’s bundled, and no modifier can save it.
Now, here’s the part to put on your calendar. CMS issued its proposed physician fee schedule for CY 2027 on July 14, 2026. It would cut payment when an office E/M claim with modifier 25 shares a day with a procedure that has a 0-, 10- or 90-day global period, and CMS expects the biggest negative impact to be in dermatology, otolaryngology and podiatry. The cut is 50 percent on the lower-valued service, trade groups and analysts said. The comment window closed September 14. CMS typically publishes final rules in early November, and the proposed start date is January 1, 2027. Nothing is final until CMS says so.
Run the math now. Pull last year’s Medicare claims, flag every visit with modifier 25 plus a procedure, and cut the lower-valued line in half. That number is your worst-case scenario. Some commercial plans copy Medicare changes, so plan for a ripple.
Medical or cosmetic: where the line sits
Payers want a documented medical reason before they pay to remove a lesion. Seborrheic keratoses, skin tags, benign nevi and scar revisions all get denied as cosmetic when the note says only “patient requests removal”. Symptoms change the answer. Bleeding, irritation from clothing, rapid change, or a lesion that can’t be ruled out as malignant should be included in the note, along with the site, size, and a photo if the payer requests one.
When a service really is cosmetic, get a signed financial responsibility form before you start. For Delaware Medicaid members, that advance notice is the only thing that allows you to collect payment.
Payer requirements to check before you treat
Medicare first. Novitas Solutions publishes coverage policies for the procedures you bill most, and contractors can set their own diagnosis and documentation rules. Read them before the first claim of the year, not after the first denial.
Highmark Blue Cross Blue Shield Delaware and the national carriers publish their reimbursement policies on modifier 25 and bundled procedures, and these don’t always match Medicare. Download each one and note the review date.
Confirm authorisation rules for any biologic for psoriasis or atopic dermatitis and before Botox for hyperhidrosis for Medicaid plans. These services will generally require prior authorisation, and the approval will usually specify the drug, dose, and diagnosis. Any mismatch on any of these will sink the claim.
The denials that keep coming back
Most dermatology denials trace to a short list. Modifier 25 is missing, or the note doesn’t support it. The diagnosis doesn’t match the procedure (an acne code on a wart destruction). The excision was coded based on the pathology size. Eligibility was checked on the wrong date or against the wrong plan. A Medicaid claim went out before the primary insurance was billed.
All five are fixable at the front end, which is cheaper than appealing them later.
Frequently asked questions
What is the timely filing limit for dermatology claims in Delaware?
Delaware Medicaid requires claims to be submitted initially within 12 months of the date of service with limited exceptions for retroactive eligibility and delayed primary payer determinations. Medicare Part B also gives you a year. Commercial limits are in each carrier’s contract and are often shorter, so check them.
Does Delaware Medicaid pay for cosmetic dermatology?
No. DMAP’s general policy manual identifies cosmetic procedures and cosmetic-purpose drugs as noncovered. The same service may be medically necessary, i.e., removal of a bleeding or inflamed lesion, when supported by the note.
When should a dermatology practice use modifier 25?
Modifier 25 is used when the provider performs a significant, separately identifiable E/M service on the same date as a procedure with a zero or ten-day global period. The work must go beyond just deciding to perform the procedure. Visits that lead to a 90-day global procedure take modifier 57.
How are multiple biopsies billed?
You bill one unit per lesion, however many passes it takes. For several lesions, bill the primary code for the first (11104 for a punch biopsy, for example) and the matching add-on (11105) for each additional lesion.
Can I bill a Medicaid patient when a claim is denied?
Only in the situations the DMAP manual lists. For a non-covered or medically unnecessary service, you must have told the patient before the service that DMAP won’t pay and documented it, and the patient still chose to proceed. A denial resulting from your billing error does not allow you to bill the patient.
How long does Delaware law give an insurer to pay a clean claim?
30 days from receipt as per Reg. 1310. Scrub it before it goes out. Claims with errors may not be counted as clean.
What’s changing for modifier 25 in 2027?
On July 14, CMS proposed cutting payment for a same-day office E/M with modifier 25 when it is performed with a procedure that has a 0-, 10-, or 90-day global period. CMS typically publishes the final rule in early November, and the proposed effective date is January 1, 2027.
Should a small dermatology practice in Delaware outsource its billing?
It makes sense most of the time if your staff spend more time working denials than preventing them or when one person does coding, posting and follow-up themselves. A speciality billing partner has coders that are familiar with dermatology edits and a team that works denials on a daily basis. Request the monthly denial rate and the days in A/R reports.
Get your dermatology claims paid the first time
Dermatology claims are taken from your hands and put into the hands of coders who know the 11102 to 17315 range, like the back of their hand. You get cleaner first-pass claims, faster follow-up on unpaid claims and a plain English monthly report of what was billed, paid and denied.
Send your last 90 days of denied dermatology claims through the contact page at claimstonebilling and ask for a review. You’ll see which denials are recoverable and what keeps causing the rest.