Quest AD-Detect® Beta-Amyloid 42/40 Ratio, Plasma

Message

EDTA tube must be spun down, plasma transfered to a polypropylene tube, and frozen within an hour of collection.

Test Code

11786

Alias/See Also

LAB01202

CPT Codes
0346U

Includes

ABeta 42
ABeta 40
ABeta 42/40 Ratio

Preferred Specimen

1.2 mL plasma collected in K2 EDTA tube

Minimum Volume

0.6 mL

Instructions

Collect blood into a K2 EDTA Plasma tube and mix by inversion 10 times. Centrifuge to separate plasma from cells within 1 hour of collection. Carefully transfer plasma into a non-conical polypropylene tube or one of the Quest issued polypropylene (non-conical) pour-off/ transfer tubes. If unable to centrifuge within 1 hour of collection, store tube on ice. Store frozen.

Note: Quest Diagnostics does not perform this test for individuals under the age of 18. Pre-test and post-test counseling is strongly recommended.

Transport Container

Transport tube

Transport Temperature

Frozen

Specimen Stability

Room temperature: Unacceptable
Refrigerated: 72 hours
Frozen -20° C: 32 days
Frozen -70° C: 77 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Moderate or gross hemolysis • Specimen collected in a glass, polystyrene, or polycarbonate tube

Methodology
Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS)

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule

Sun

Report Available

4-12 days

Reference Range

ABeta 42	Not established	pg/mL
ABeta 40	Not established	pg/mL
ABeta 42/40 Ratio	≥0.170

Clinical Significance

This LC-MS/MS assay measures beta-amyloid 40 (AB40) as well as AB42 in plasma, rather than AB42 alone. This permits the normalization of beta amyloid levels circulating in plasma in different patients. Using the ratio of beta-amyloid 42/beta-amyloid 40, improves sensitivity and specificity for detecting Alzheimer's disease.

Performing Laboratory

Quest Diagnostics Nichols Institute-San Juan Capistrano, CA

33608 Ortega Highway

San Juan Capistrano, CA 92675-2042

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.