PNH by Flow Cytometry

General Information

Lab Name

PNH by Flow Cytometry

Lab Code


Epic Name

PNH by Flow Cytometry



The University of Washington Hematopathology laboratory is currently receiving requests for flow cytometry testing that exceed our capacity. We anticipate that turnaround times will be delayed in a subset of MRD flow cytometry cases, and we will no longer be able to regularly provide STAT call backs for MRD flow cases. Additionally, UW Hematopathology is unable to accept flow cytometry reference testing from new clients and will be limiting service to a subset of current clients.

In Paroxysmal Nocturnal Hemoglobinuria (PNH), a clonal marrow stem cell population gives rise to circulating mature hematopoietic cells lacking the expression of a variety of different cell surface proteins whose common feature is their linkage to the cell membrane via a glycosyl-phosphatidyl-inositol (GPI) linkage, a linkage that is deficient in the PNH clone. Similar findings may also be seen in aplastic anemia and myelodysplasia, although the frequency of GPI-deficient cells is lower. GPI-deficiency is most easily assessed in the erythroid, granulocytic and monocytic lineages, and flow cytometry is the method of choice for their detection. The flow cytometric assay evaluates for a loss of expression of the following GPI-linked antigens: CD59 on red cells, CD14 and FLAER on monocytes, and CD24 and FLAER on granulocytes. The assay can detect as little as 0.01% GPI-deficient cells in each cell lineage.


Borowitz et al (2010) Guidelines for the diagnosis and monitoring of paroxysmal nocturnal hemoglobinuria and related disorders by flow cytometry. Cytometry Part B 78B:211 to 230.


CD59, GPI deficient, Paroxysmal Nocturnal Hemoglobin


Code Name
PNHSTA PNH by Flow Cytometry Status
PNHSPD PNH by Flow Cytometry Spec Descr
PNHHP PNH Case Number
PNHRES PNH by Flow Cytometry Result
PNHINT PNH by Flow Cytometry Interp
PNHREV PNH by Flow Cytometry Results Reviewed by:
PNHMET PNH by Flow Cytometry Method



Flow Cytometry

Reference Range

See individual components

Interferences and Limitations

The assay is performed by flow cytometric immunophenotyping and interpreted by a trained hematopathologist. The assay has been validated for the diagnosis and monitoring of patients with hematopoietic neoplasms.


Ordering & Collection

Specimen Type

Peripheral Blood


Blood: 6 mL blood in LAVENDER top (EDTA) tube

Unacceptable: Bone Marrow, Formalin fixed, paraffin embedded specimens

Please note: Green top tubes are accepted for testing.

Forms & Requisitions

Hematopathology Requisition

Handling Instructions

Samples should be ambient and delivered to the laboratory without delay. Optimal results are achieved when samples are received within: 24-48 hours of collection

Samples submitted outside of this range will be evaluated for quality using appropriate internal controls and the results qualified appropriately.


requested: 6 mL blood



LIS Dept Code

Hematopathology (HP)

Performing Location(s)

Other Hematopathology

UW Hematopathology Laboratory, G7-800
Fred Hutchinson Cancer Center
825 Eastlake Avenue E.
Seattle, WA 98109



Available STAT?


Billing & Coding

CPT codes

88184, 88185x7, 88187



Interfaced Order Code