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For hours, walk-ins and appointments.Synonyms
- % CD20 B Lymphocytes
- CD20
- CD20 on B Lymphocytes
Special Instructions
Collect specimens Monday through Wednesday only.
This test is not approved for New York state clients.
Expected Turnaround Time
3 - 4 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Specimen Requirements
Specimen
Whole blood
Volume
Fill tube(s) to capacity
Minimum Volume
0.5 mL
Container
Yellow-top (ACD) tube or lavender-top (EDTA) tube
Collection
Invert tube 8 to 10 times immediately after collection. To preserve cellular viability, collect specimen so it will arrive in the laboratory within 72 hours of collection. Indicate date and time of venipuncture on the tube(s) and on the test request form.
Storage Instructions
Room temperature
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 4 days |
Refrigerated | Unstable |
Frozen | Unstable |
Causes for Rejection
Hemolysis; specimen refrigerated or frozen; clotted specimen; contaminated specimen
Test Details
Use
This test can be used in assessing therapeutic B-cell depletion in any clinical context, including Multiple Sclerosis, malignancies, autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosus and membranous glomerulonephritis among others, and treatment or prevention of acute humoral rejection in positive crossmatch renal transplant recipients. It can be used in the evaluation of CD20 deficiency in patients with suspected CD19 deficiency (humoral immunodeficiency), and it can be used to confirm the complete absence of B cells in suspected primary humoral immunodeficiencies using both CD19 and CD20 markers.
Limitations
Timing and consistency in the timing of blood collection is critical in monitoring patients for lymphocyte subsets.
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration. This test is performed in a CLIA certified laboratory and is intended for clinical purposes.
Methodology
Flow cytometry
Additional Information
Monoclonal antibody-based therapies block available CD20-binding sites and, therefore, the antibody used for this flow cytometric assay cannot recognize the CD20 molecule on B cells. The concomitant use of the CD19 marker provides information on the extent of B-cell depletion when using this particular treatment strategy. This Flow Cytometry panel is also useful for confirming the complete absence of B cells in suspected primary humoral immunodeficiencies.
References
Carmichael KF, Abayomi A. Analysis of diurnal variation of lymphocyte subsets in healthy subjects and its implication in HIV monitoring and treatment. Afr J Med Med Sci. 2006 Mar;35(1):53-57.17209328
Dimitrov S, Benedict C, Heutling D, Westermann J, Born J, Lange T. Cortisol and epinephrine control opposing circadian rhythms in T-cell subsets. Blood. 2009 May 21:113(21):5134-5143.19293427
Dimitrov S, Lange T, Nohroudi K, Born J. Number and function of circulating antigen-presenting cells regulated by sleep. Sleep. 2007 Apr;30(4):401-411.17520784
Kronfol Z, Nair M, Zhang Q, Hill EE, Brown MB. Circadian immune measures in healthy volunteers: relationship to hypothalamic-pituitary-adrenal axis hormones and sympathetic neurotransmitters. Psychosom Med. 1997 Jan-Feb;59(1):42-50.9021865
Malone JL, Simms TE, Gray GC, Wagner KF, Burge JR, Burke DS. Sources of variability in repeated T-helper lymphocyte counts from HIV 1-infected patients: total lymphocyte count fluctuations and diurnal cycle are important. J Acquir Immune Defic Syndr (1988). 1990;3(2):144-151.1967309
Paglieroni TG, Holland PV. Circannual variation in lymphocyte subsets, revisited. Transfusion. 1994 Jun;34(6):512-516.7912866
Payandeh Z, Bahrami AA, Hoseinpoor R, et al. The aplications of anti-CD20 antibodies to treat various B cell disorders. Biomed Pharmacother. 2019 Jan;109:2415-2426.30551501
Pescovitz MD. Rituximab, an anto-CD20 monoclonal antibody: history and mechanism of action. Am J Transplant. 2006 May;6(5 Pt 1):859-866.16611321
Robillard N, Avet-Loiseau H, Garaand R, et al. CD20 is associated with a small mature plasma cell morphology and t(11;14) in multiple myeloma. Blood. 2003 Aug 1;102(3):1070-1071.12702507
Tedder TF, Schlossman SF. Phosphorylation of the B1 (CD20) molecule by normal and malignant human B lymphocytes. J Biol Chem. 1988 Jul 15;263(20):10009-10015.2454914
van Zelm MC, Reisli I, van der Burg M, et al. An antibody-deficiency syndrome due to mutatiuons in the CD19 gene. N Engl J Med. 2006 May 4;354(18):1901-1912.16672701
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 096930 | CD20 B Cells | 94689-7 | 096931 | % CD19-B Cells | % | 8117-4 |
| 096930 | CD20 B Cells | 94689-7 | 096932 | % CD20-B Cells | % | 8119-0 |
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