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HelpTest Code Lymphocyte Subset analysis T Cells CD45 RA and RO
Additional Codes
Study includes: CD3, CD4, CD8, CD45 RA/RO. Panels can be ordered alone, or in combination with other T and B panels. Duplicate tests will not be charged.
Clinical System Name
T and B CD3, Subsets, CD45RA and RO
Synonyms
CD45 RA/RO
RA/RO
45 RA/RO
45RA/RO
RA RO
Lymphocyte Subset
Sample Requirements
Specimen: Whole Blood
Container(s): Lavender/EDTA; Dk Green/Na Heparin also acceptable from referring labs if CBC & differential results submitted from the same collection
Preferred Vol: 2-3 mL
Minimum Vol: 2 mL; no microtainers
Note: Specimens received after 1430 will be held and testing will be performed the next working day.
| Collected in-house at Seattle Children's | Collected off-site (including SCH Bellevue, SCH North and SCH South) | |
|---|---|---|
| M-Th | collect any time | collect any time |
| Friday | collect any time | ok if received at SCH main lab same day, if not do not collect |
| Saturday | ok if collected before 12 noon | do not collect |
| day before a holiday | ok if collected before 12 noon | must be received at SCH main lab before 12 noon |
| Sunday | ok if collected after 12 noon (to be tested next morning) |
ok if collected after 12 noon (to be tested next morning) |
| Sunday before a holiday Monday | do not collect | do not collect |
| Holiday | ok if collected after 12 noon (to be tested next morning) | ok if collected after 12 noon (to be tested next morning) |
Children's Outpatient Blood Draw areas and Community Services - order "Lymphocyte Subset" and select Paper Requisition under order comments (specific tests will be ordered in Cell Markers Lab) and submit copy of requisition with specimen.
Processing Instructions
Reject due to: clotted specimen, microtainers, refrigerated
Spin: N
Aliquot: N
Temp: RT - DO NOT REFRIGERATE
Note: Have Core Lab run specimen through hematology analyzer and send a copy of the results and community services requisition (if applicable) with specimen to Cell Markers.
Storage location: Days: Transport specimen, copy of community services requisition (if applicable), and labels to Cell Markers (tube station #181). Eves/Nights: Store specimen, copy of community services requisition (if applicable), and labels in the Cell Markers RT box in CPA.
Off-site collection: Keep whole blood at room temperature. Referring labs may send CBC w/differential results from the same collection along with the sample.
Stability
| Temperature | Time |
|---|---|
| Room temp | EDTA - 30 hours; Heparin - 48 hours |
| Refrigerated | N |
| Frozen | N |
Availability
| STAT | Performed | TAT |
|---|---|---|
| N | M-F, Sa (0730-1200) | 2-3 days |
Note: limited specimen stability - see Sample Requirements
Performing Laboratory
Seattle Children's Laboratory
Department
Department: Cell Markers
Phone Number: 206-987-2560
CPT Codes
contact Laboratory Client Services at (206)-987-2617
Methodology
Method: Flow Cytometry
Analytical Volume: Dependent on patient's white count and testing requested. If <1mL is collected please ask to recollect in order to obtain minimum volume of 1mL. If unable to recollect and sample volume is <0.350mL (350uL) please cancel and do not send to Cell Markers for testing. If unable to recollect and sample is between 0.350mL and 1mL (350ul-1mL) please send to Cell Markers, but let patient and/or patient family know that there is a strong possibility that we will not be able to perform the testing due to low volume. We will do our best and understand that the volume needed is dependent on the white count and the specific antibodies that are ordered. (The higher the white count the less volume needed. The more antibodies ordered the more volume needed.)
Limitations:
Reference Range
Reference values accompany patient report.
Description
The CD45RA/RO assay is used in the evaluation of immunodeficiency. CD45RA and CD45RO are isoforms of the CD45 antigen that are typically expressed on T Cells in identifiable patterns using flow cytometry.
Clinical Utility
CD45RA and CD45RO are isoforms of the CD45 antigen that are typically expressed on T Cells in identifiable patterns using flow cytometry. Typically CD45RA and CD45RO are run against each other and against CD3 and CD4 or CD8. This is a 5-color flow cytometry study.
CD45RA is the long isoform of CD45 and is expressed on naive T cells. CD45RO is the shorter isoform, and is expressed on T cells that have encountered antigens. In clinical immunology, this distinction between CD45RA+ versus CD45RO+ T-cell subsets is particularly useful to determine the status of the naive T-cell compartment relative to their thymus origin. Primary immunodeficiency disorders characterized by decreased/absent thymic output often show decreased CD45RA+ (naive) T cells.