CSF Alzheimer's Markers

Test Code

92433

Alias/See Also

CSF Alzheimer's Markers
ADMARK
92433
Alzheimer's Markers CSF
Phospho-Tau CSF

CPT Codes
84393, 82234, 84394

Includes

Beta-Amyloid (1-42), CSF
tTau, CSF
pTau181, CSF
tTau/Abeta42 Ratio
pTau181/Abeta42 Ratio

Preferred Specimen

1 mL CSF collected in CSF tube 63.614.625 (Sarstedt)

Minimum Volume

0.7 mL

Instructions

Perform lumbar puncture (LP) using gravity drip collection method. Avoid the use of syringes or tubings. Perform lumbar puncture (LP) before noon. Do not use the first 2 mL of CSF for AD Biomarker measurement. Subsequently, collect at least 1.0 mL of CSF directly into the CSF tube 63.614.625 (Sarstedt) for AD biomarker measurements. (Note: The mark on the tube indicates 2.5 mL).

Collect clear (non-hemolytic) CSF in a new CSF tube. Collection of CSF for other purposes can follow thereafter, if required. Do not process the CSF sample before transport to the measuring site (i.e., no mixing/inverting, no tube transfers, no aliquoting, no freezing and normally no centrifugation) until measurement. It is strongly recommended that the sample be kept at 2 to 8°C during transport and storage up to the time of measurement.

Transport Container

CSF tube 63.614.625 (Sarstedt)

Transport Temperature

Refrigerated (cold packs)

Specimen Stability

Room temperature: 5 days
Refrigerated: 14 days
Frozen: 56 days

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

Gross hemolysis

Methodology
Electrochemiluminescence (ECLIA)

Setup Schedule

Set up: Mon, Wed, Fri, Sat; Report available: 3-5 days

Reference Range

Beta-Amyloid (1-42), CSF	Not established
tTau, CSF	Not established
pTau181, CSF	Not established
tTau/Abeta42 Ratio	≤0.28
pTau181/Abeta42 Ratio	≤0.023

Clinical Significance

Elecsys Beta Amyloid (1 42) CSF II, Phospho-Tau (181P) CSF and Elecsys Total Tau CSF are in vitro electrochemiluminescence immunoassays for the measurement of the Beta Amyloid (1 42) (Abeta42), PTau (181P) and Total Tau (tTau) protein concentration in cerebrospinal fluid (CSF) from adult patients aged 55 years and older being evaluated for Alzheimer's disease (AD) and other causes of cognitive impairment to generate a tTau/Abeta42 and pTau-181/Abeta42 ratios and values. A negative result, defined as tTau/Abeta42 and Phospho-Tau (181P) ratio values below cutoff or an Abeta42 value above the measuring range, are consistent with a negative amyloid positron emission tomography (PET) scan result. A negative result reduces the likelihood that a patient?s cognitive impairment is due to AD. A positive result, defined as tTau/Abeta42 and pTau181/Abeta42 ratio value above cutoff, is consistent with a positive amyloid PET scan result. A positive result does not establish a diagnosis of AD or other cognitive disorder. The tTau/Abeta42 and pTau181/Abeta42 ratio results are used as an adjunct to other clinical diagnostic evaluations.

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.