Flow Cytometry, Ektacytometry, DNA Ploidy, and S-phase Fraction
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Clinical coverage and medical necessity policy for use of flow cytometry (cell surface markers, DNA ploidy, S‑phase fraction) and ektacytometry, including indications considered medically necessary, investigational/experimental exclusions, and coding guidance affecting ordering clinicians and laboratories.
No material clinical or coverage changes in this revision.
Coverage Criteria
inv-01: Flow cytometry (cell surface markers) — Medically necessary
Covered when ANY of the following indications are present.
Extracted verbatim list of indications from policy.
inv-02: DNA ploidy and S‑phase fraction — Conditional medical necessity
Covered when ALL of the following are met.
Eligible localized cancers: endometrial adenocarcinoma; gastric cancer; mediastinal neuroblastoma; medulloblastoma; ovarian carcinoma; partial hydatidiform mole; prostatic adenocarcinoma; renal cell adenocarcinoma; urinary bladder carcinoma.
inv-03: Ektacytometry — Medically necessary
Covered when ALL of the following are met.
OGE is a screening/diagnostic test with reported high sensitivity and specificity for HS in validation studies; test codes include 0305U and relevant ICD‑10 codes such as D58.0.
inv-04: Experimental and investigational
Not covered (considered experimental/investigational) for the following.
Effectiveness not established per policy.
Flow cytometry‑derived DNA ploidy and S‑phase fraction (SPF) testing is considered experimental/investigational and not covered for multiple solid tumor types listed in this policy because effectiveness for these indications has not been established. Specific cancers named as not covered include, but are not limited to, breast cancer, cervical cancer, colorectal cancer, non‑small cell lung cancer, pediatric intracranial tumors, and small cell lung cancer.
Guideline summaries cited in the policy (ASCO and related updates) note insufficient evidence to support routine use of flow cytometry‑derived DNA/ploidy measures in clinical practice for breast cancer, and explicitly state that DNA ploidy or % S‑phase by flow cytometry should not be used to determine prognosis of early‑stage colorectal cancer. The policy therefore restricts routine application of these tests except where specified conditions apply.
Validation studies of the BIOCHIP mosaic‑based IIF assay have significant limitations that affect generalizability and clinical adoption: reported studies were performed in a limited number of countries, often enrolled small sample sizes (for example, a cross‑sectional study with n = 40), and recruited largely Caucasian normal controls. Additional reported drawbacks include low case‑to‑control ratios, selection bias, and in some studies an absence of direct comparison with established methods such as ELISA. These limitations support the conclusion that BIOCHIP assays require broader, prospective validation across diverse populations before routine clinical use can be recommended.
Based on the NIH consensus and the evidence summarized in this policy, the routine use of flow cytometry‑derived DNA content (ploidy) or S‑phase fraction for prognostic or therapeutic decision making in cancers is not indicated except for the small set of localized tumors specifically listed when results will affect treatment decisions.
Professional society guidance and the policy narrative do not support routine application of DNA ploidy or S‑phase fraction testing for prognosis in several tumor types. ASCO updates and related guideline statements cite insufficient evidence for routine DNA/ploidy testing in breast cancer and recommend against using flow‑cytometrically derived DNA ploidy or % S‑phase to determine prognosis for early‑stage colorectal cancer; the policy extends noncoverage/experimental status to other cancers where effectiveness has not been established.
Covered Indications and Use Cases
inv-37: See flow cytometry medically necessary indications (cell surface markers), conditional use of DNA ploidy/S‑phase for listed localized cancers when results will affect treatment, and ektacytometry for RBC cytoskeleton/hydration disorders when morphology is inconclusive.
See flow cytometry medically necessary indications (cell surface markers); DNA ploidy/S‑phase testing is conditional for listed localized cancers when results will affect treatment; ektacytometry is indicated for RBC membrane/cytoskeleton disorders when morphology is inconclusive.
See policy sections for full lists and test frequency limits.
inv-38: Diagnosis and differential diagnosis of hereditary spherocytosis and other RBC membrane disorders — OGE diagnostic performance cited
Covered when ALL of the following are met.
OGE parameters and cutoffs described in cited validation studies; use when routine morphology and standard laboratory tests are inconclusive.
inv-39: Adjunctive evaluation in suspected pulmonary sarcoidosis using BAL lymphocyte subpopulation analysis (CD4/CD8 ratio)
Covered when the following adjunctive criterion is met.
Used as adjunctive evidence; not solely diagnostic.
inv-40: Research/assay development for platelet/leukocyte adhesion and monitoring therapeutic effects (e.g., vaso-occlusive crisis therapies)
Covered only for research or investigational use.
Policy lists these approaches as experimental/investigational for clinical use due to unestablished effectiveness.
inv-41: Serologic testing for pemphigus and related autoimmune blistering disease using BIOCHIP mosaic IIF — limited validation studies
Covered in limited validation contexts; broader validation needed before routine adoption.
Validation studies cited from multiple countries; limitations include small sample sizes and limited ethnic diversity.
inv-42: Screening and evaluation of hereditary spherocytosis and other red blood cell membrane disorders — OGE cited (Llaudet-Planas 2018; Huisjes 2020)
Covered when ALL of the following are met.
Use when standard testing is inconclusive; reported diagnostic metrics available in cited literature.
inv-43: Serologic diagnosis and evaluation of autoimmune blistering diseases (pemphigus vulgaris/foliaceus/bullous pemphigoid) — BIOCHIP mosaic IIF evidence summarized
Covered in investigational/limited-validation contexts.
Studies cited include cross‑sectional comparisons with direct immunofluorescence and ELISA; limitations noted in policy background.
inv-44: Prognostic assessment in various solid tumors using DNA ploidy and S-phase fraction — multiple cited references
Covered when ALL of the following are met.
See policy reference list for extensive citations regarding prognostic studies.
Coding and Billing
| 86360 | T cells; absolute CD4 and CD8 count, including ratio. |
| 88182 | Flow cytometry, cell cycle or DNA analysis. |
| 88184 | Flow cytometry, cell surface, cytoplasmic, or nuclear marker, technical component only; first marker. |
| 88185 | each additional marker (List separately in addition to code for first marker). |
| 88187 | Flow cytometry, interpretation; 2 to 8 markers. |
| 88188 | 9 to 15 markers. |
| 88189 | 16 or more markers. |
| 0303U | Hematology, red blood cell (RBC) adhesion to endothelial/subendothelial adhesion molecules, functional assessment, whole blood, with algorithmic analysis and result reported as an RBC adhesion index; hypoxic. |
| 0304U | Hematology, red blood cell (RBC) adhesion to endothelial/subendothelial adhesion molecules, functional assessment, whole blood, with algorithmic analysis and result reported as an RBC adhesion index; normoxic. |
| 0305U | Hematology, red blood cell (RBC) functionality and deformity as a function of shear stress, whole blood, reported as a maximum elongation index. |
| B20 | Human immunodeficiency virus [HIV] disease [T cell monitoring]. |
| C16.0 - C16.9 | Malignant neoplasm of stomach [gastric, localized without metastatic disease]. |
| C38.1 - C38.2 | Malignant neoplasm of anterior and posterior mediastinum [neuroblastoma, localized without metastatic disease]. |
| C54.1 | Malignant neoplasm of endometrium [localized without metastatic disease]. |
| C56.1 - C56.9 | Malignant neoplasm of ovary [localized without metastatic disease]. |
| C57.4 | Malignant neoplasm of uterine adnexa, unspecified [localized without metastatic disease]. |
| C61 | Malignant neoplasm of prostate. |
| C64.1 - C64.9 | Malignant neoplasm of unspecified kidney, except renal pelvis [localized without metastatic disease]. |
| C67.0 - C67.9 | Malignant neoplasm of bladder [localized without metastatic disease]. |
| C71.0 - C71.9 | Malignant neoplasm of brain [medulloblastoma in adults only]. |
| C18.0 - C21.8 | Malignant neoplasm of colon, rectosigmoid junction, rectum, anus and anal canal. |
| C34.00 - C34.92 | Malignant neoplasm of bronchus and lung [non-small cell lung cancer]. |
| C50.011 - C50.929 | Malignant neoplasm of breast. |
| C53.0 - C53.9 | Malignant neoplasm of cervix uteri. |
| D43.0 - D43.3 | Neoplasm of uncertain behavior of brain and cranial nerves [pediatric intracranial only]. |
| No codes listed |
Provider Actions and Administrative Notes
Verify code‑specific coverage criteria and billing codes
Certain CPT/HCPCS procedure codes are listed as covered only when the policy's clinical selection criteria are met; verify coverage and any authorization requirements prior to billing.
Prior authorization not specified in policy excerpt
The policy text does not specify any prior authorization requirements for the tests in this excerpt; confirm payer-specific prior auth rules separately if needed.
No explicit prior authorization or impacted codes listed
No explicit prior authorization requirements or affected billing codes are stated in the supplied excerpt; check administrative/billing resources for plan-specific rules before ordering.
Document expected impact on treatment decisions
When ordering DNA ploidy or S‑phase fraction testing, document that the prognostic information obtained will affect treatment decisions for the patient.
- Policy: DNA ploidy/S‑phase is medically necessary for listed localized cancers ONLY when prognostic information will affect treatment decisions.
- Test is usually performed only once per tumor lifetime, typically after diagnosis and before treatment.
BIOCHIP validation and study limitations
BIOCHIP mosaic‑based IIF validation is limited by small sample sizes, selection bias, and lack of ethnically diverse control populations; note these limitations when ordering or interpreting BIOCHIP results.
- Validation studies performed in limited countries and with primarily Caucasian control populations.
- Some studies had small sample sizes (e.g., n=40) and lacked comparison with ELISA in all cases.
Denial risk for non‑supported indications
Testing for DNA ploidy or S‑phase fraction for routine prognostic or therapeutic purposes is considered not indicated except for the listed localized cancers; ordering for unsupported indications may be denied.
- Policy: routine use of DNA ploidy/S‑phase for prognosis/therapy not indicated; experimental/investigational for cancers such as breast, cervical, colorectal, NSCLC, pediatric intracranial tumors, and small cell lung cancer.
- Order only when the policy's medical necessity criteria are met to avoid claim denial.
Tests not supported by clinical guidelines for routine management
Specialty guidelines and cited reviews do not recommend routine use of flow cytometry‑derived DNA ploidy or S‑phase fraction for prognosis in many cancers; avoid using these tests for management decisions unless policy exceptions apply.
- ASCO and guideline updates note insufficient evidence to support routine use of DNA/ploidy by flow cytometry for breast cancer and early‑stage colorectal cancer.
- Authors and guideline statements cited in the policy conclude these measures are not indicated for routine prognostic management.
Consult full policy for additional provider actions
Fallback: consult the full policy/source document for any additional provider requirements or clarifications not captured in this excerpt.
Refer to complete source document
Fallback: review the full document source for any missing administrative or billing instructions not present in this chunk.
Verify policy history and coding details in source
Fallback: check the complete policy history and coding tables in the full source for updates or code-specific notes not in this excerpt.
Ordering documentation — document medical necessity and clinical impact
There are no explicit ordering documentation requirements listed in these chunks beyond documenting medical necessity and, for DNA ploidy/S‑phase testing, documenting intended impact on treatment decisions.
- Policy requires documentation that prognostic information will affect treatment decisions for DNA ploidy/S‑phase testing.
- No other specific ordering paperwork, provider-type privileges, or forms are specified in the provided excerpts.
No extra provider actions specified
No additional provider actions are specified in this document excerpt; follow the policy's medical necessity criteria and local administrative rules when ordering and billing.
Ordering Requirements
Document clinical indication and expected treatment impact
Document the clinical indication and medical necessity when ordering DNA ploidy or S‑phase fraction testing; specifically state that results will influence treatment decisions.
- Policy: DNA ploidy/S‑phase medically necessary for listed localized cancers ONLY when prognostic information will affect treatment decisions.
- Provider should document clinical indication supporting medical necessity.
No explicit ordering privileges or provider‑type requirements
The policy does not specify any provider-type ordering privileges or restrictions; tests are discussed in the context of specialist workups but no explicit ordering privileges are listed.
- Tests are described in specialist contexts (e.g., bone marrow workup, BAL for pulmonary disease, tumor evaluation) but no explicit provider-type requirements are stated.
Not Covered / Experimental
The policy lists specific procedure codes and test types that are not covered because they are considered experimental or investigational. Examples include RBC adhesion index assays billed with HCPCS codes 0303U and 0304U, and flow cytometry‑derived DNA ploidy/S‑phase testing when ordered for cancers identified in the experimental/investigational list (e.g., breast, cervical, colorectal, non‑small cell lung, pediatric intracranial tumors, small cell lung cancer).
Routine ordering of flow cytometry for DNA ploidy or S‑phase fraction as prognostic tests in cancers is not supported by guideline statements and is therefore listed as not covered for those routine prognostic uses (for example, breast cancer and early‑stage colorectal cancer). Coverage is limited to the specific localized cancers enumerated in the policy when prognostic results will influence treatment decisions.
BIOCHIP assays are described as promising but currently not recommended for routine clinical use without further validation. The policy highlights study limitations — small sample sizes, selection bias, and limited ethnic diversity among controls — which may preclude coverage of BIOCHIP testing for diagnostic purposes until larger, prospective, and comparative validation studies are available.
Definitions
Flow cytometry separates and quantifies cell populations using cell surface phenotype and fluorescence‑based measurements, and can measure nuclear DNA content (ploidy) and the percentage of cells in S‑phase (SPF) to estimate proliferation. Osmotic gradient ektacytometry measures red blood cell deformability and hydration (e.g., osmoscan/OGE), producing parameters such as elongation index that help diagnose RBC membrane and hydration disorders when morphology is inconclusive.
Background and Evidence Limitations
Multiple limitations in the BIOCHIP evidence base reduce confidence in its diagnostic performance: studies were conducted in a small number of countries, validation cohorts often recruited only Caucasian normal controls, sample sizes were small, and some studies lacked comparisons to established assays (e.g., ELISA). Review authors emphasize the need for prospective studies with more diverse control populations and larger case‑control ratios to validate BIOCHIP performance.
Summarizing the evidence, the policy states that the routine use of flow cytometry‑derived DNA content (ploidy) or S‑phase fraction for prognostic or therapeutic purposes in cancers is not indicated except for the narrow list of localized tumors for which the policy allows conditional use when results will affect treatment decisions. Guideline statements (ASCO) and the NIH consensus are cited to support this stance.
Revision History
Policy originally became effective.
Initial policy established coverage framework for flow cytometry, ektacytometry, DNA ploidy, and S-phase fraction testing.
Policy underwent routine review (last review date recorded).
Next policy review scheduled.
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