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HelpTest Code PLAFL Platelet Surface Glycoprotein by Flow Cytometry, Blood
Useful For
Identification of markedly decreased CD41 (GPIIb) and CD61 (GPIIIa) expression levels, which are diagnostic for Glanzmann thrombasthenia
Identification of markedly decreased CD42a (GPIX) and CD42b (GPIb-alpha) expression levels, which are diagnostic for Bernard-Soulier syndrome
Identification of decreased GPVI expression, which suggests collagen receptor deficiency
Identification of decreased CD49b (GPIa), which suggests collagen receptor deficiency
Highlights
This test serves as a confirmatory test for platelet aggregation studies.
Markedly decreased platelet surface glycoprotein expression levels are diagnostic for various hereditary or acquired platelet disorders.
Special Instructions
Method Name
Immunophenotyping
Reporting Name
Platelet Glycoprotein Flow, BSpecimen Type
Whole Blood ACDShipping Instructions
Specimen must be shipped ambient and arrive within 4 days of draw.
Ship specimen overnight in an Ambient Shipping Box-Critical Specimens Only (T668) following the instructions in the mailer.
Necessary Information
Platelet Esoteric Testing Patient Information is required. Testing may proceed without the patient information, however, the information aids in providing a more thorough interpretation. Ordering providers are strongly encouraged to fill out the form and send with the specimen.
Specimen Required
Supplies: Ambient Shipping Box-Critical Specimens Only (T668)
Collection Container/Tube: ACD solution A or B
Specimen Volume: 6 mL
Pediatric Volume: 1 mL
Collection Instructions: Do not transfer blood to other containers.
Specimen Minimum Volume
Adult: 1 mL
Pediatric 200 mcL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole Blood ACD | Ambient | 4 days |
Reject Due To
| Gross hemolysis | Reject |
| Fully Clotted | Reject |
| Gross lipemia | OK |
Clinical Information
Platelets have essential roles in primary hemostasis. Exposed collagen at a vascular damage site can activate platelets via collagen receptor GPVI and GPIa and bind shear-stretched multimeric VWF proteins, which subsequently interact with the platelet surface receptor, GPIb-V-IX. Upon full activation, platelets can aggregate by binding to fibrinogen through activated GPIIb-GPIIIa receptors. Deficiency of platelet surface glycoproteins can cause bleeding diathesis.
Platelet flow cytometric analysis is the preferred method to assess hereditary platelet disorders due to quantitative surface glycoprotein (GP) deficiencies. GP expression levels can be measured by using fluorescent-conjugated GP-specific antibodies and their fluorescent intensities can be compared to normal ranges of various glycoproteins.
|
CD Number |
Glycoprotein Name |
Integrin Name |
|
CD41 |
GPIIb |
Alpha 2b |
|
CD42a |
GPIX |
NA |
|
CD42b |
GPIb-alpha |
NA |
|
CD49b |
GPIa |
Alpha 2 |
|
CD61 |
GPIIIa |
Beta 3 |
|
NA |
GPVI |
NA |
Reference Values
GPIIb CD41: ≥70.0% (Normal Range-Median)
GPIIIa CD61: ≥70.0% (Normal Range-Median)
GPIX CD42a: ≥70.0% (Normal Range-Median)
GPIb-alpha CD42b: ≥70.0% (Normal Range-Median)
GPIa CD49b: ≥60.0% (Normal Range-Median)
Interpretation
|
CD Markers |
% Reference Range Median |
Comments |
|
CD41 and CD61 |
50%-69% (Marginally) |
Marginally decreased platelet surface receptors CD41 (GPIIb) and CD61 (GPIIIa) are of uncertain clinical significance. This finding could be a laboratory artifact due to a suboptimal sample condition, benign polymorphisms, or a heterozygous state of Glanzmann thrombasthenia. Recommend correlation with patient’s clinical findings and results of platelet functional studies, and consider repeating platelet glycoprotein profile studies by flow cytometry to verify the present finding if clinically indicated. |
|
30%-50%: (Moderately) Â <30%: (Markedly) |
Platelet surface expression of CD41 (GPIIb) and CD61 (GPIIIa) are moderately or markedly decreased. This finding is suggestive of a variant of Glanzmann thrombasthenia. Recommend correlation with patient’s clinical findings and results of platelet functional studies, and consider repeating platelet glycoprotein profile studies by flow cytometry to verify the present finding if clinically indicated. |
|
|
CD42a and CD42b  |
50%-69% (Marginally) |
Marginally decreased platelet surface receptors CD42a (GPIX) and CD42b (GPIb-alpha) are of uncertain clinical significance. This finding could be a laboratory artifact due to a suboptimal sample condition, benign polymorphisms, or a heterozygous state of Bernard-Soulier syndrome. Recommend correlation with patient's clinical findings and results of platelet functional studies, and consider repeating platelet glycoprotein profile studies by flow cytometry to verify the present finding if clinically indicated. |
|
30%-50%: (Moderately) Â <30%: (Markedly) |
Platelet surface expression of CD42a (GPIX) and CD42b (GPIb-alpha) are moderately or markedly decreased. This finding is suggestive of a variant of Bernard-Soulier syndrome. Recommend correlation with patient's clinical findings and results of platelet functional studies, and consider repeating platelet glycoprotein profile studies by flow cytometry to verify the present finding if clinically indicated. |
|
|
CD49b |
30%-59% (Marginally) |
Marginally decreased platelet surface receptor CD49b (GPIa) is of uncertain clinical significance. This finding could be a laboratory artifact due to a suboptimal sample condition, a benign polymorphism, or a variant of platelet collagen receptor glycoprotein Ia/IIa deficiency. Recommend correlation with patient's clinical findings and results of platelet functional studies, and consider repeating platelet glycoprotein profile studies by flow cytometry to verify the present finding if clinically indicated. |
|
10%-30% (moderately) Â <10% (Markedly) |
Platelet surface expression of CD49b (GPIa) is moderately or markedly decreased. This finding is suggestive for a variant of a variant of platelet collagen receptor glycoprotein Ia/IIa deficiency. Recommend correlation with patient's clinical findings and results of platelet functional studies, and consider repeating platelet glycoprotein profile studies by flow cytometry to verify the present finding if clinically indicated. |
|
|
GPVI |
50%-69% (Marginally) |
Marginally decreased platelet surface receptor glycoprotein VI (GPVI) is of uncertain clinical significance. This finding could be a laboratory artifact due to a suboptimal sample condition, a benign polymorphism or a variant of platelet collagen receptor GPVI deficiency. Recommend correlation with patient's clinical findings and results of platelet functional studies, and consider repeating platelet glycoprotein profile studies by flow cytometry to verify the present finding if clinically indicated. |
|
30%-50% (moderately) Â <30% (Markedly) |
Platelet surface expression of glycoprotein VI (GPVI) is moderately or markedly decreased. This finding is suggestive of a variant of a variant of platelet collagen receptor GPVI deficiency. Recommend correlation with patient's clinical findings and results of platelet functional studies, and consider repeating platelet glycoprotein profile studies by flow cytometry to verify the present finding if clinically indicated. |
Cautions
Suboptimal sample conditions due to improper blood draw, transportation, or storage may cause fluctuation of platelet surface receptors and consequently influence the results of platelet surface receptor measurement by flow cytometry.
Supportive Data
The platelet glycoprotein flow cytometry method was established in the Mayo Clinic Special Coagulation Laboratory in 2009. Between the years of 2009 to 2014, a total of 155 clinical patients at Mayo Clinic were tested. The flow cytometry results were compared with the final impressions of platelet light transmission aggregation testing. There were 7 samples that had flow cytometric features of Glanzmann thrombasthenia, 2 samples that had flow cytometric features of Bernard-Soulier syndrome, and 3 samples that had flow cytometric features of May-Hegglin anomaly. All flow cytometric results were concordant with platelet light transmission aggregation results and other clinical findings.
Clinical Reference
1. Miller, JL. Glycoprotein analysis for the diagnostic evaluation of platelet disorders. Semin Thromb Hemost. 2009;35(2):224-232
2. Kannan M, Ahmad F, Yadav BK, et al. Carrier detection in Glanzmann thrombasthenia: comparison of flow cytometry and Western blot with respect to DNA mutation. Am J Clin Pathol. 2008;130(1):93-98
3. Savoia A, Pastore A, De Rocco D, et al: Clinical and genetic aspects of Bernard-Soulier syndrome: searching for genotype/phenotype correlations. Haematologica. 2011;96(3):417-423
4. Nurden AT, Freson K, Selifsohn U. Inherited platelet disorders. Haemophilia. 2012;18(4):154-160
5. Spurgeon BEJ, Naseem KM. Platelet Flow Cytometry: Instrument Setup, Controls, and Panel Performance. Cytometry B Clin Cytom. 2020;98(1):19-27
6. Frelinger AL, 3rd, Rivera J, Connor DE, et al. Consensus recommendations on flow cytometry for the assessment of inherited and acquired disorders of platelet number and function: Communication from the ISTH SSC Subcommittee on Platelet Physiology. J Thromb Haemost. 2021;19(12):3193-3202
Method Description
Flow cytometric immunophenotyping of peripheral blood platelets is performed using the following antibodies:
Panel: CD41 (IIb), CD42a (IX), CD42b (Ib-alpha), CD49b (GPIa), CD61 (GPIIIa), and GPVI.
For sample quality purposes, CD62P is evaluated.
Using whole blood collected in ACD (A or B), platelet surface GPIa, Ib-alpha, IIb, IIIa, VI and IX expression levels are measured by flow cytometry method. Platelets in whole blood are stained with various fluorochrome-labeled primary antibodies and fixed. Then the platelet surface fluorescent intensities of various bound antibodies are measured by flow cytometers. Platelets are first gated by forward and side scatter. Mean fluorescent intensities are recorded and converted to percentage of a median fluorescent intensity of a normal donor study of 20 healthy donors. If the percentage of expression of a glycoprotein (GP) is lower than the corresponding normal range, a deficiency of a GP is detected.(Unpublished Mayo Method)
Day(s) Performed
Monday through Saturday
Report Available
1 to 2 daysSpecimen Retention Time
14 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
88184-Flow cytometry; first cell surface, cytoplasmic or nuclear marker
88185-Flow cytometry; additional cell surface, cytoplasmic or nuclear marker (each) X5
88187-Flow cytometry interpretation, 2 to 8 markers
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| PLAFL | Platelet Glycoprotein Flow, B | 93320-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| CK111 | GPIIb CD41 | 93319-2 |
| CK112 | GPIIIa CD61 | 93318-4 |
| CK113 | GPIX CD42a | 93317-6 |
| CK114 | GPIb-alpha CD42b | 93316-8 |
| CK115 | GPIa CD49b | 93315-0 |
| CK116 | GPVI | 93314-3 |
| CK117 | Final Diagnosis | 93313-5 |
Forms
1. Platelet Esoteric Testing Patient Information is required.
2. If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.