Ordering Recommendation

Use to monitor subclinical paroxysmal nocturnal hemoglobinuria and eculizumab treatment. Preferred initial diagnostic test is Paroxysmal Nocturnal Hemoglobinuria (PNH), High Sensitivity, RBC and WBC (2005006).

New York DOH Approval Status

This test is not New York state approved. Alternative testing that is New York approved is available. See Ordering Recommendations.

Specimen Required

Patient Preparation

New York State Clients: Testing is only approved for the Paroxysmal Nocturnal Hemoglobinuria (PNH), High Sensitivity, RBC and WBC (ARUP test code 2005006) on whole blood specimens.


Lavender (EDTA), pink (K2EDTA), or green (sodium or lithium heparin).

Specimen Preparation

Transport 4 mL whole blood. (Min: 0.5 mL)

Storage/Transport Temperature


Unacceptable Conditions

Clotted or hemolyzed specimens.


New York State Clients: Testing is only approved for the Paroxysmal Nocturnal Hemoglobinuria (PNH), High Sensitivity, RBC and WBC (ARUP test code 2005006) on whole blood specimens.


Ambient: 4 days; Refrigerated: 4 days; Frozen: Unacceptable


Quantitative Flow Cytometry




1-3 days

Reference Interval

By report

Interpretive Data

This high-sensitivity RBC assay tests for CD59 expression on erythrocytes using flow cytometry. It was developed according to published guidelines (Cytometry B Clin. Cytom. 2010; 78:211) and as updated in 2018 (Cytometry B Clin. Cytom. 2018; 94B:49). The lower limit of quantification is 0.02 percent for PNH RBCs (based on 250,000 cells analyzed). The lower limit of detection for PNH RBCs is 0.008 percent.

RBC analysis quantifies Type II and Type III RBC clones when the percentage of PNH RBCs is greater than 1 percent. Glycophorin A (CD235a) is used to gate the RBC population, and CD59 is the GPI-linked antigen. Recent RBC transfusions may decrease the percentage of PNH cells measured in RBCs (Cytometry 2000; 42:223). The presence of a subclinical PNH population in myelodysplastic bone marrow disorders, such as aplastic anemia or refractory anemia, may correlate with a positive immunotherapeutic response (Blood 2006; 107, 1308-1314).

For the most accurate measurement of the PNH clone size, order Paroxysmal Nocturnal Hemoglobinuria, High Sensitivity, WBC (ARUP test code 2005003) to assist with therapeutic decisions in conventional PNH.

For initial diagnosis of PNH and analysis of both RBCs and WBCs, order Paroxysmal Nocturnal Hemoglobinuria (PNH), High Sensitivity, RBC and WBC (ARUP test code 2005006).

Patient Retesting Recommendations: The frequency of testing is dictated by clinical and hematologic parameters. Repeat testing is indicated upon any significant change in clinical or laboratory parameters and is suggested at least annually for routine monitoring. In the setting of aplastic anemia, international guidelines recommend screening for PNH at diagnosis, and every 3 to 6 months initially, reducing the frequency of testing if the proportion of GPI-deficient cells has remained stable over an initial two-year period (Int J Lab Hematol 2019;41 Suppl 1:73-81).

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the U.S. Food and Drug Administration. This test was performed in a CLIA-certified laboratory and is intended for clinical purposes.

Compliance Category

Laboratory Developed Test (LDT)


If >1% PNH RBCs are detected, then PNH RBC TYPE reflex will be added at no additional charge.

Hotline History


CPT Codes

86356 x2


Component Test Code* Component Chart Name LOINC
2004367 Total (II and III) CD59-deficient RBC 33662-8
3005033 RBC PNH Phenotype 93479-4
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • CD59 and Glycophorin A
  • Eculizumab treatment monitoring
  • PI-Linked
Paroxysmal Nocturnal Hemoglobinuria, High Sensitivity, RBC