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Total Tau, CSF (CLEIA)

Order Code
2925040
CPT
84394
Test Details
Synonyms

T- Tau, tTau

TAT

7 days

Methodology

Chemiluminescent enzyme immunoassay (CLEIA)

Reference Interval

Negative ≤ 348

Remarks

Total tau (t-tau) is a non-specific marker of neuronal injury. Elevated levels may occur in Alzheimer’s disease (AD), other neurodegenerative disorders, traumatic brain injury, stroke, seizures, and inflammatory or infectious CNS conditions. Abnormal results should always be interpreted in the context of the clinical assessment, cognitive findings, neuroimaging, and complementary biomarkers (e.g., CSF Amyloid-β 42/40 ratio, p-tau181, p-tau217), as well as any recent neurological events (seizures, stroke, head injury etc.).

Within the AT(N) framework, t-tau contributes to evaluating whether the overall biomarker profile is compatible with AD or suggests an alternative cause. In confirmed or suspected Alzheimer’s disease, elevated t-tau may indicate more rapid disease progression, but it does not correlate with tau pathology and should not be used for staging tau burden.

Performing Location

Accredited NRL Laboratory

Testing Frequency

Weekly

Test Overview

Alzheimer’s disease (AD), the most common cause of dementia, is a neurodegenerative disorder characterized by the accumulation of extracellular amyloid plaques and intracellular neurofibrillary tangles within cortical and limbic brain regions.

This assay is designed to measure total tau (t-tau), a neuronal protein that binds to microtubules in axons and plays a key role in maintaining microtubule structure and stability. In Alzheimer’s disease, the characteristic CSF biomarker profile includes reduced β-amyloid 1-42 alongside elevated total tau and phosphorylated tau (p-tau), reflecting amyloid deposition and neuronal injury.

While increased CSF total tau supports the presence of neurodegeneration, it is not disease-specific and may also be markedly elevated in other conditions, including acute stroke and Creutzfeldt–Jakob disease. As such, total tau results should be interpreted in conjunction with amyloid biomarkers, phosphorylated tau, and the clinical context.

Specimen Type

CSF

Volume

0.5 mL

Specimen Container

Sarstedt sterile polypropylene tubes

Patient Preparation

Preferably, the lumbar puncture should be performed in the morning.

Collection

Perform the lumbar puncture at the L3/L4 or L4/L5 intervertebral space. Collect the cerebrospinal fluid in an appropriate polypropylene tube and transport it frozen at –20°C.

Specimen Stability
Temperature Period
Frozen 2 months
Order Code
2925040
CPT
84394
Test Details
Synonyms

T- Tau, tTau

TAT

7 days

Methodology

Chemiluminescent enzyme immunoassay (CLEIA)

Reference Interval

Negative ≤ 348

Remarks

Total tau (t-tau) is a non-specific marker of neuronal injury. Elevated levels may occur in Alzheimer’s disease (AD), other neurodegenerative disorders, traumatic brain injury, stroke, seizures, and inflammatory or infectious CNS conditions. Abnormal results should always be interpreted in the context of the clinical assessment, cognitive findings, neuroimaging, and complementary biomarkers (e.g., CSF Amyloid-β 42/40 ratio, p-tau181, p-tau217), as well as any recent neurological events (seizures, stroke, head injury etc.).

Within the AT(N) framework, t-tau contributes to evaluating whether the overall biomarker profile is compatible with AD or suggests an alternative cause. In confirmed or suspected Alzheimer’s disease, elevated t-tau may indicate more rapid disease progression, but it does not correlate with tau pathology and should not be used for staging tau burden.

Performing Location

Accredited NRL Laboratory

Testing Frequency

Weekly

Test Overview

Alzheimer’s disease (AD), the most common cause of dementia, is a neurodegenerative disorder characterized by the accumulation of extracellular amyloid plaques and intracellular neurofibrillary tangles within cortical and limbic brain regions.

This assay is designed to measure total tau (t-tau), a neuronal protein that binds to microtubules in axons and plays a key role in maintaining microtubule structure and stability. In Alzheimer’s disease, the characteristic CSF biomarker profile includes reduced β-amyloid 1-42 alongside elevated total tau and phosphorylated tau (p-tau), reflecting amyloid deposition and neuronal injury.

While increased CSF total tau supports the presence of neurodegeneration, it is not disease-specific and may also be markedly elevated in other conditions, including acute stroke and Creutzfeldt–Jakob disease. As such, total tau results should be interpreted in conjunction with amyloid biomarkers, phosphorylated tau, and the clinical context.

Specimen Type

CSF

Volume

0.5 mL

Specimen Container

Sarstedt sterile polypropylene tubes

Patient Preparation

Preferably, the lumbar puncture should be performed in the morning.

Collection

Perform the lumbar puncture at the L3/L4 or L4/L5 intervertebral space. Collect the cerebrospinal fluid in an appropriate polypropylene tube and transport it frozen at –20°C.

Specimen Stability
Temperature Period
Frozen 2 months