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UW Health SMPH
American Family Children's Hospital

UW Hospital and Clinics Lab Test Directory

Test Name: Flow Cytometry, Total Lymphocyte Analysis with CD20

Test Code(s): TLA20 / HCTLA20

CPT Code(s): 86355, 86357, 86359, 86360, 86356

Test Description: Test Component:

Absolute lymphocyte count, percent and absolute numbers of CD3 (T-cells), CD3 CD4  (T-helper/inducer cells), CD3 CD8  (T-cytotoxic/suppressor cells), CD3-CD19+  (B-cells), CD3-CD16 CD56  (NK-cells), CD20 (B cells), CD4:CD8

Methodology: Flow Cytometry

Days Performed: Mon-Fri, dayshift- specimens accepted at anytime.

Turnaround Time: Stat: Not available stat.
Routine: 1 - 4 days.

Specimen Requirements

Specimen: Blood

Collection Instructions: An order for a WBC and differential must accompany request.

Outside clients should send WBC and differential results along with specimen. If no results accompany request, a WBC and differential will be added (see transport and limitations for more information).

Collection Container: Preferred: Lavender top

Collection Volume: Preferred: 4 mL
Pediatrics: 1 mL

Sample Analyzed: Whole Blood

Volume Required: Preferred: 1 mL
Pediatrics: 0.5 mL

Specimen Processing: Keep specimen at room temperature. Do NOT centrifuge tube.

Specimen Transport: Transport unopened tube at room temperature to UWHC Core Laboratory (B4/220) within 4 hours of collection. Maintain ambient temperature during transport. For outreach locations sending WBC and differential results along with specimen, specimen may be received within 8 hours of collection.

Unacceptable Criteria: Hemolyzed, clotted, frozen or overheated specimens are not acceptable.  Specimens older than 24 hours at time of analysis are not acceptable.

Stability: Ambient: 6 hours if WBC and Differential results do not accompany specimen, 24 hours if CBC and Differential results accompany specimen.
Refrigerated: Not acceptable
Frozen: Not acceptable


Reference Interval:

Age 18 and up: 



   %  Absolute number/uL
 CD3:  59-85  767-1903
 CD3+CD4+:  37-64  481-1464
 CD3+CD8+:  14-33  247-595
 CD3-CD19+:  6-24  88-454
 CD3-CD16+CD56+:  6-24  77-427
 CD20:  5-16  60-280
 CD4:CD8 ratio:  1.2-3.7  


Please contact UWHC Flow Laboratory at (608) 263-3868 for pediatric reference intervals.

Test Limitations:

Absolute values will not be calculated if WBC and differential request or results are not received.

Additional Information:

This test was developed and its performance characteristics determined by the UWHC Clinical Laboratories. This test meets the standards for clinical testing. This test should not be regarded as investigational or for research use. The US Food and Drug Administration (FDA) has not approved or cleared this test; however, the FDA has determined that such clearance or approval is not necessary.

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