CPT 87164Laboratory

Dark field exam spec collj

CPT code 87164 covers a dark field microscopy examination of a specimen, a specialized laboratory technique that illuminates specimens against a dark background to detect certain microorganisms like the bacteria that causes syphilis.

Showing rates for

National Average

Base Medicare rate

$18.11

This calculator gives a typical-case estimate using standard Medicare modifier rules. Actual payment depends on payer policies, documentation, code-specific CMS status indicators, and locality. Verify before billing.

RVU breakdown

Work RVU

0.37

PE RVU (NF)

0.18

MP RVU

0.01

Total RVU

0.56

Conversion factor: 32.3465 · Source: CMS MPFS RVU25A · Confidence: High

NCCI bundling edits

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Billing tips

Document specimen source and collection time precisely - dark field microscopy requires fresh specimens examined within 20 minutes of collection for accurate results
Impact: Reduces denial risk by 40-50%; delayed specimen processing is a common reason for medical necessity denials
Link to appropriate ICD-10 codes indicating suspected or confirmed syphilis (A51.0, A51.2, A53.9) or contact with/exposure to syphilis (Z20.2)
Impact: Ensures medical necessity documentation; improper diagnosis coding causes 30% of denials for this code
Bill only once per specimen regardless of number of slides examined; do not unbundle or bill multiple units for the same collection
Impact: Prevents overbilling audits and automatic denials; Medicare allows only one unit per specimen source
Verify CLIA certification for high-complexity testing is current before performing and billing dark field microscopy
Impact: Non-compliance can result in 100% claim denial and potential exclusion from Medicare program
Document negative results thoroughly with notation of adequate specimen quality and examination technique
Impact: Protects against medical necessity challenges; negative results with poor documentation face 25% higher audit risk
For specimens from multiple anatomical sites on same patient, document medical necessity for each site and consider modifier 59
Impact: Supports reimbursement for additional tests when clinically appropriate; can secure additional $18.11 per justified site

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Frequently asked questions

What is the Medicare reimbursement rate for CPT code 87164 in 2025?

The 2025 Medicare national average reimbursement rate for CPT 87164 is $18.11 for both facility and non-facility settings, based on 0.56 total RVUs and a conversion factor of 32.3465.

What is dark field microscopy examination CPT 87164 used to diagnose?

CPT 87164 is primarily used to diagnose primary syphilis by directly visualizing Treponema pallidum spirochetes in fresh specimens from chancres or other suspicious lesions. It provides immediate results before serological tests become positive.

How long does a specimen remain viable for dark field microscopy?

Specimens for dark field microscopy must be examined within 15-20 minutes of collection while organisms remain motile. Delayed examination significantly reduces test sensitivity and may justify denial of payment due to specimen inadequacy.

Can CPT 87164 be billed multiple times on the same day?

Yes, but only with proper documentation and modifiers. Use modifier 91 for repeat testing for clinical monitoring, or modifier 59 when examining specimens from distinct anatomical sites. Each instance requires separate medical necessity documentation.

What CLIA certification level is required to bill CPT 87164?

Dark field microscopy (CPT 87164) is classified as high-complexity testing under CLIA regulations, requiring a CLIA certificate for high-complexity testing and personnel with specific training and competency in this specialized microscopy technique.

What diagnosis codes support medical necessity for CPT 87164?

Primary diagnosis codes include A51.0 (primary genital syphilis), A51.2 (primary syphilis of other sites), A53.9 (syphilis unspecified), and Z20.2 (contact with and exposure to syphilis). Document clinical findings supporting suspicion of active syphilitic lesion.

Is dark field microscopy still commonly used or has it been replaced by other syphilis tests?

While serological tests (RPR, VDRL, treponemal antibody tests) are more commonly used, dark field microscopy remains valuable for diagnosing primary syphilis before antibodies develop and in situations requiring immediate diagnosis from lesion material, particularly in specialized STD clinics and research settings.