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HelpTest ID AD2AR PrecivityAD2, Reflex to Apolipoprotein E, Plasma
Ordering Guidance
This blood test is intended for use in patients aged 55 and older with signs or symptoms of mild cognitive impairment or dementia who are undergoing evaluation for Alzheimer disease or other forms of cognitive decline, and who have not had prior apolipoprotein E proteotyping or APOE genotyping.
Shipping Instructions
1. Specimens must be shipped frozen on dry ice.
2. Place labeled aliquot tubes inside a larger tube or vial for transport.
Specimen Required
Supplies: Screw cap micro tube, 2 mL, PCR Performance Tested, Low protein-binding (T983)
Collection Container/Tube: 10 mL Purple top (K EDTA)
Submission Container/Tube: Two 2-mL screw cap micro tubes
Specimen Volume: 3 mL in 2 tubes, each containing 1.5 mL
Collection Instructions:
1. Centrifuge within two hours of collection.
2. Label two 2-mL screw-cap micro tubes.
3. Aliquot 1.5 mL of plasma into each labeled micro tube.
4. Freeze plasma (no longer than 2 hours after collection) at or below -20° C.
Useful For
Assisting in the evaluation of adult patients, aged 55 years and older, with signs or symptoms of mild cognitive impairment or dementia who are being assessed for Alzheimer disease and other causes of cognitive decline
Determining APOE E4 status to aid in medical management and treatment decisions when the PrecivityAD2 blood test result is positive
This test is not intended for patients younger than 55 years, or for use as a screening test in patients without signs or symptoms of cognitive, or for serial testing for assessment of longitudinal changes.
Highlights
The PrecivityAD2 blood test measures amyloid beta (Abeta) 42/40 ratio and percent tau phosphorylated at threonine-217 (%p-tau217). The results are then combined and used in a proprietary statistical algorithm to calculate the Amyloid Probability Score 2 (APS2). The APS2, Abeta 42/40 ratio and %p-tau217 are reported, however, individual Abeta42, Abeta40, phosphorylated tau217 and non-phosphorylated tau217 concentrations are not reported. For patients who receive a positive PrecivityAD2 test result, additional testing is performed to measure the apolipoprotein E isoforms E2, E3, and E4.
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| C2NAP | Precivity-ApoE | No | No |
Testing Algorithm
When this test result is positive, then apolipoprotein E testing will be performed at an additional charge.
Method Name
Immunoprecipitation/Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
PrecivityAD2 Reflex to ApoESpecimen Type
PlasmaSpecimen Minimum Volume
See Specimen Required
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma | Frozen | ||
Reference Values
Amyloid Probability Score 2 (APS2) (range of 0-100):
Negative: 0-47
Positive: 48-100
Abeta42/40 Ratio:
≥0.095 Consistent with absence of amyloid plaques
Percent p-tau217:
<4.2% consistent with absence of brain amyloid plaques
ApoE Proteotype
E2/E2, E2/E3, E2/E4, E3/E3, E3/E4, E4/E4
-E3 is the most common allele.
-E4 allele is associated with increased risk of amyloid plaques.
-E2 allele is associated with lower risk of amyloid plaques.
Day(s) Performed
Monday through Friday
Report Available
15 days post sample receipt from MCLPerforming Laboratory
C2N Diagnostics LLCTest Classification
C2N Diagnostics has developed and determined the analytical and clinical validity performance characteristics of this Laboratory Developed Test (LDT). This assay has been validated pursuant to CLIA regulations and is used for clinical purposes. This assay has not been cleared or approved by the FDA.CPT Code Information
81599
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| AD2AR | PrecivityAD2 Reflex to ApoE | Not Provided |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| C2RG | Amyloid Probability Score 2 (APS2) | Not Provided |
| C2RGF | APS2 Result | Not Provided |
| C2RH | APS2 Result Interpretation | Not Provided |
| C2RI | APS2 Result Reference Interval | Not Provided |
| C2RJ | APS2 Description | Not Provided |
| C2RK | Percent p-tau217 | Not Provided |
| C2RL | Percent p-tau217 Reference Interval | Not Provided |
| C2RLD | Percent p-tau217 Description | Not Provided |
| C2RM | Abeta42/40 Ratio | Not Provided |
| C2RN | Abeta42/40 Ratio Reference Interval | Not Provided |
| C2RND | Abeta42/40 Ratio Description | Not Provided |
| C2RO | Test Description | Not Provided |
| C2RP | Limitations of Test Result | Not Provided |
| C2RQ | Methods and Assay Category | Not Provided |
| C2RR | References | Not Provided |
| C2RRC | Report Comment | Not Provided |
| C2RRF | Performing Site | Not Provided |
NY State Approved
NoForms
If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen.