Is the lab bill after a skin biopsy covered by insurance?
Usually yes. The stain is a medical lab service most plans cover, but it lands on the deductible and shows up as a second bill from a lab the patient never met. Code 88342 is the first special antibody stain a pathologist adds to a skin biopsy when the routine slide does not answer the question.
Usually yes
Paid, but it hits the deductible
First stain only
88342 is the first antibody on a sample. Every stain after it bills as 88341, so one biopsy can carry several lines the patient never expected.
Caps per specimen
Many plans pay one 88342 plus a set number of add on stains per specimen, then deny the rest as not supported by the pathology report.
Outside lab risk
When the slides go to a lab outside the network, the patient gets billed at out of network rates for work they never picked.
Bill arrives later
The lab bill shows up weeks after the visit. Running the plan before the biopsy lets the desk warn the patient while they are still in the chair.
What would a real check show for this patient's 88342?
Pick a sample plan and type your per-sample fee. This is the visibility a real-time check gives the desk for every actual patient, in under a second.
Eligibility readout · 88342
Sample- Coverage
- Active, in network lab required
- Frequency
- No stain limit stated by the plan
- Patient share
- Type your fee to see it
Estimate from a sample plan. A real check reads the actual plan in under a second.
When 88342 is the right code
- First antibody stain run on that tissue sample
- Extra antibodies on that specimen bill as 88341
- The report names each antibody and the reason
- Computer measured stains use 88360 or 88361
- Fungus and tissue stains use 88312 instead
Documentation payers expect
Payers expect the pathology report to name each antibody, why it was ordered and what it showed. Stains run as a standing panel, with no report language explaining the need, are the ones taken back on review.
Why the stain line gets denied
What arrives after the biopsy
The patient sees the office charge first, then a lab claim weeks later carrying 88305 for the routine read plus 88342 and any 88341 add on stains. If the result is skin cancer, the next visit brings treatment codes such as 11602 or 17311, each with its own patient share. Deductible plans feel all of it. Checking status, deductible left and network flags before the biopsy is what turns that second envelope into something the patient was warned about.
88342, quick answers
Why did I get a bill from a lab I never visited?
Skin biopsies are read by a pathologist, often at an outside lab. That lab bills your plan separately from the office, so one visit can produce two claims.
Does Medicare cover 88342?
Yes, under Part B when the pathology report supports the stain. The Part B deductible and coinsurance apply, and Medicare's claim edits cap how many stain lines it will pay on one specimen.
Can I ask which lab my biopsy goes to?
Yes, and it is worth asking before the biopsy. Surprise billing protections mostly cover care given inside a facility, so a lab your office mails a sample to can still bill at its own rate.
Is the stain included in the biopsy charge?
No. The biopsy, the routine slide read and each stain are separate lines, which is why the total runs higher than patients expect.
What if my plan pays for only some of the stains?
The lab or office can appeal with the pathology report showing why each antibody was needed. Plans often pay once the report explains the question being answered.
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Related: 88305 · 88341 · 88312
CPT is a registered trademark of the American Medical Association. This page is Valian's own plain-English summary for front-desk teams, not official CPT descriptor text, and is not billing or clinical advice. Coverage patterns are common plan behaviors; every plan differs. Verify benefits before the visit.