CPT Code 88142: Thin Layer Pap Test Billing, 2026 Rates, and G0123 vs. 88142

What is CPT code 88142?

CPT code 88142 is a laboratory code that reports cervical or vaginal cytopathology collected in preservative fluid, prepared with an automated thin layer method, and screened manually under physician supervision. It is the code for a liquid-based Pap test, such as ThinPrep or SurePath, and Medicare pays it at $20.26 nationally in 2026 on the Clinical Laboratory Fee Schedule.

• Who bills it: The laboratory that prepares and reads the slide bills 88142, while the OB/GYN practice that collects the sample bills the visit and, for Medicare screening, Q0091.
• Screening vs. diagnostic: For a Medicare screening Pap, labs bill G0123 instead of 88142, and 88142 is reserved for diagnostic Paps tied to symptoms, prior abnormal results, or follow-up.
• Diagnosis pairing: Routine well-woman Paps usually carry Z01.419 or Z01.411 for the exam and Z12.4 for cervical cancer screening, while diagnostic Paps carry the finding, such as R87.610 or Z87.410.

CPT 88142 Description and Related Pap Codes

The full CPT descriptor for 88142 is cytopathology, cervical or vaginal (any reporting system), collected in preservative fluid, automated thin layer preparation; manual screening under physician supervision. Each phrase narrows the code. Any reporting system means Bethesda or another format qualifies. Preservative fluid means a liquid-based collection vial. Automated thin layer preparation means the lab uses a processor to make the slide. Manual screening means a cytotechnologist reads it under a pathologist’s supervision.

Change any one of those elements and the code changes. Automated screening of the same thin layer slide moves to 88174, and automated screening followed by manual rescreening moves to 88175. Manual screening with rescreening is 88143. Conventional smears on glass slides fall in the 88150 to 88167 range, and Medicare screening versions use G-codes and P-codes.

Code	What it reports	2026 Medicare rate
88142	Thin layer Pap, manual screening	$20.26
88143	Thin layer Pap, manual screening and rescreening	$23.04
88174	Thin layer Pap, automated screening	$25.37
88175	Thin layer Pap, automated screening and manual rescreening	$26.61
G0123	Medicare screening thin layer Pap, cytotechnologist screening	$20.26
88141	Physician interpretation of an abnormal cervical or vaginal cytology	$24.05
87624	High-risk HPV, pooled result	$35.09

Laboratory rates are national limitation amounts from the CMS Clinical Laboratory Fee Schedule for the fourth quarter of 2026. CPT 88141 is paid under the Physician Fee Schedule and rises to about $24.47 in 2027 under the CY 2027 final rule, released November 4, 2026.

One question we hear constantly from OB/GYN practice managers is why the Pap code never appears on their own claims. Unless the practice runs a CLIA-certified cytology lab, it does not. The practice bills the collection and the visit, and the reference laboratory bills 88142 or G0123 directly to the payer.

When is 88142 used instead of G0123?

Use G0123 when a Medicare patient receives a covered screening Pap with no signs, symptoms, or history requiring a diagnostic test. Use 88142 when the Pap is diagnostic, such as follow-up after an abnormal result, a history of cervical dysplasia, or symptoms, and for most commercial payers, which accept CPT codes for both screening and diagnostic Paps.

The two codes describe the same laboratory work. G0123 exists because Medicare covers screening Pap tests as a separate statutory benefit under National Coverage Determination 210.2, Screening Pap Smears and Pelvic Examinations for Early Detection of Cervical and Vaginal Cancer. Medicare covers a screening Pap every 24 months for most women, and every 12 months for women at high risk or women of childbearing age with an abnormal Pap in the preceding 36 months.

Medicare’s National Correct Coding Initiative edits make the choice binary. The October 2026 practitioner edits pair 88142 with G0123 using a modifier indicator of 0, so the two can never be billed together for the same date. The same edits bundle 88142 into 88143, 88174, and 88175, and bundle the conventional smear codes 88150 to 88167 into 88142. A lab bills one cytology code per specimen, and its Medically Unlikely Edit limit is 1 unit per day.

Diagnosis codes drive which path the claim follows. A screening Pap carries Z12.4, Encounter for screening for malignant neoplasm of cervix, or Z12.72 for vaginal screening after hysterectomy. A diagnostic Pap carries the reason, such as R87.610 for atypical squamous cells of undetermined significance, R87.612 for a low grade squamous intraepithelial lesion, or Z87.410 for personal history of cervical dysplasia.

The most common issue we see providers run into is a requisition that does not tell the lab which path applies. When the order lacks the high-risk indicator or the abnormal history, the lab bills G0123 to Medicare, the frequency edit fires, and the patient receives a bill the practice could have prevented.

CPT 88142 Reimbursement in 2026 and 2027

Medicare pays 88142 at a national limitation amount of $20.26 in 2026, the same as G0123. Laboratory codes are not adjusted by geographic indices or the physician conversion factor, so the 2.31% Physician Fee Schedule cut for 2027 does not apply to 88142. What does apply in 2027 is a separate change to how lab rates are set.

Under section 6226 of the Consolidated Appropriations Act, 2026, CMS will reset most Clinical Laboratory Fee Schedule rates for 2027 using private payer rates collected from January 1 through June 30, 2025, and reported to CMS from May 1 through July 31, 2026. The CY 2027 Physician Fee Schedule final rule confirms that any reduction is capped at 15% per year for 2027 through 2029, after a 0% cap for 2026.

For 88142, that cap means the 2027 national rate cannot fall below about $17.22, even if private payer data supports a lower number. As of November 9, 2026, the final 2027 lab rate for 88142 had not been posted, so laboratories should load the new figure when CMS releases the January 2027 fee schedule file.

For the OB/GYN practice, the codes that matter are on the collection side. Q0091, obtaining a screening Pap smear for a Medicare patient, pays about $46.09 nationally in 2026 and about $46.33 in 2027. Many practices pair that collection with other gynecologic services on the same visit, such as CPT 58300 IUD insertion, which requires its own documentation. For a full view of how the 2027 rule affects the rest of your schedule, review your contracted rates line by line rather than relying on the headline cut.

How do you bill a Pap test correctly?

Bill a Pap test by matching the code to the payer and purpose. The practice bills the visit and specimen collection, the laboratory bills 88142 or G0123, and both sides use diagnosis codes that tell the payer whether the test was screening or diagnostic. Medicare frequency limits and NCCI edits decide what pays.

1. Confirm whether the Pap is screening or diagnostic before the specimen leaves the office.
2. Mark the lab requisition with the correct diagnosis, including any high-risk factor or abnormal history.
3. Bill Q0091 for Medicare screening collection, and do not bill it for a diagnostic Pap.
4. Check the patient’s last covered screening date against Medicare’s 24-month or 12-month limit.
5. Issue an Advance Beneficiary Notice when a screening Pap falls inside the frequency window and no high-risk criteria apply.
6. Order HPV testing, such as 87624 or 87626, with its own supporting diagnosis when co-testing.
7. Reconcile lab results to the visit so abnormal findings trigger the correct follow-up codes.

Each step maps to a denial we see across practices. A requisition coded as screening when the patient has a history of LSIL pushes the lab toward G0123 and a frequency denial. A Q0091 billed with a diagnostic Pap draws a medical necessity rejection. A missing ABN converts a covered patient conversation into a write-off.

Prenatal Paps add another layer. A Pap collected at the first prenatal visit is a laboratory service separate from the global obstetric package, but the visit itself may fall under antepartum billing rules. Our breakdown of modifier TH for antepartum billing explains how payers treat prenatal visits billed outside the global package.

In our experience matching providers with billing partners, practices that print Pap-specific diagnosis prompts on their lab requisitions see fewer lab-side denials, because the lab no longer guesses which Medicare path the test belongs to.

Common CPT 88142 Billing Mistakes

Most 88142 problems start in the exam room, not the lab. The first is billing the Pap on the practice’s own claim. Unless the practice owns a CLIA-certified cytology laboratory, 88142 belongs to the lab, and the practice claim should show only the visit, the collection code where applicable, and any procedures performed.

The second is mixing screening and diagnostic codes. G0123 and 88142 cannot share a date of service under NCCI, and Q0091 is a screening collection code. When the Pap is diagnostic, the visit code carries the collection work, and Q0091 does not belong on the claim.

The third is ignoring frequency. Medicare’s 24-month screening limit is counted in months, not calendar years: at least 23 months must pass after the month of the last covered screening. A patient screened in March 2025 is not eligible for another low-risk screening Pap until March 2027, regardless of what the practice’s annual well-woman schedule says.

The fourth is coding the well-woman exam alone. Z01.419 or Z01.411 describes the gynecological exam, but Z12.4 tells the payer a cervical cancer screening occurred. Leaving off Z12.4 can block preventive coverage for the Pap even when the exam pays. Practices that also perform office procedures on the same visit, such as diagnostic hysteroscopy reported as CPT 58558, should keep the procedure diagnosis separate from the screening diagnosis.

Providers often come to us after a payer audit flagged repeated Q0091 claims attached to diagnostic Paps, or a lab sent back months of patient complaints about screening bills. Both patterns are fixable with a requisition template and a short coding reference for the front desk.

Frequently Asked Questions

Next Steps

CPT 88142 is a lab code, but most of the revenue it protects sits on the OB/GYN side of the claim. Start with a 90-day review of every Pap your practice collected: compare the diagnosis on your claim with the diagnosis on the lab requisition, check that Q0091 appears only with Medicare screening Paps, and confirm every out-of-window screening had a signed ABN.

Then extend the same review to the gynecologic procedures billed on the same visits. Our guides to CPT 58300 IUD insertion and CPT 58558 hysteroscopy cover the documentation those codes need, and our coverage of modifier TH and antepartum billing explains how prenatal visits with Pap collection are handled. If your team does not have time to keep requisitions, frequency checks, and payer rules aligned, a billing company that specializes in OB/GYN can take that on and report denial trends back to you each month.

Finally, share the reference table of Pap codes and rates with your front desk and clinical staff. When everyone who touches the requisition knows the difference between 88142, G0123, and Q0091, fewer claims go out on the wrong path and fewer patients receive surprise screening bills in the mail weeks later.