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Test Code TBCLT T and B Cells, Total

Specimen Required

5 mL whole blood collected in an EDTA (lavender-top) tube

Specimen Minimum Volume

0.5 mL

Specimen Stability

Room temperature: 72 hours Refrigerated: Unacceptable Frozen: Unacceptable

Rejection Due To

ACD (yellow-top) tube • Sodium heparin (green-top) tube

Method Name

Flow Cytometry (FC)


Absolute Lymphocytes, Absolute CD19+ Cells, % CD19 (B Cells), Absolute CD3+ Cells, % CD3 (Mature T Cells)

Collection Container / Tube

Preferred: EDTA (lavendar-top) tube
Other Acceptable Container: None

Transport / Storage Conditions

Room temperature

Special Instructions

Do not transfer whole blood to M4 preservative.
Whole blood collected in ACD or sodium heparin (green-top) tube is not acceptable.
Volumes less than 1 mL should be submitted in a pediatric EDTA tube. Submit the EDTA tube(s) at room temperature. Do not refrigerate or freeze.

It is recommended that the sample be drawn shortly before courier pick up and be received within 24 hours.

Reference Values

See Laboratory Report

Day(s) Performed

Set up: Mon-Sat; Report available: Next day

CPT Codes

86355, 86359

Clinical Reference

Low numbers of nk celss are found in individuals who are susceptible to viral infections, including cytomegalovirus and varicella.