- MRI
- EEG
- RT-QuIC
- 14-3-3 and tau
- PRNP gene sequencing
- After counselling
- Skin and nasal samples
- Blood and urine tests
This page lists the tests in the Atlas. Each entry says what the test measures, what the studies found and how far it is from routine use. The Atlas describes tests in general. A doctor interprets any individual result, and a genetic counsellor can talk through genetic testing before anything is done.
How is CJD diagnosed?
Doctors consider a case suspected on the basis of symptoms, spinal fluid tests, an MRI brain scan and an EEG, which records the brain’s electrical activity. Confirmation needs testing of brain tissue, from a biopsy or after death. Details of the imaging and EEG tests are on MRI and EEG.
Which tests are in the Atlas?
| Entry | What it is |
|---|---|
| CSF 14-3-3 and tau | Spinal fluid markers of nerve cell damage |
| CSF PrP | Prion protein measured in spinal fluid |
| EP-QuIC | End-point quaking-induced conversion, a seeded amplification assay |
| ES-QuIC | An enhanced-sensitivity version of QuIC |
| Nano-QuIC | QuIC with added nanoparticles |
| Olfactory RT-QuIC | Amplification assay on nasal samples |
| Blood prion amplification | Amplification assays applied to blood |
| Blood markers | Other markers measured in blood |
| MRI and EEG | Imaging and electrical recording |
What is a seeded amplification assay?
These assays add a small sample, such as spinal fluid, to a mix containing normal prion protein. If misfolded prion protein is present, it makes the normal protein misfold too, and the change is read out by a signal. The Glossary defines RT-QuIC and PMCA.
What do recent studies report?
A 2026 retrospective study in Annals of Neurology modified end-point QuIC by using a deer mouse protein as the substrate. In spinal fluid from 116 patients with sporadic or inherited prion disease it reached 96.6 percent sensitivity and 100 percent specificity. Standard end-point QuIC reached 87.1 percent and second-generation real-time QuIC 72.4 percent. The gains were largest in inherited and atypical cases. The authors state that prospective, multi-laboratory validation is still needed.
A 2026 review in Lancet Neurology says seeded amplification assays have improved diagnostic accuracy and that blood-based markers are close to clinical application. It adds that tests in blood, tear fluid and urine could be easier to access.
Can I find out whether a test is available to me?
Availability depends on the country and the laboratory. A neurologist can say which tests apply to a particular case. For the research behind tests, see Therapies in development and Sources. The Atlas home lists the other sections.
Explore
- Blood markers (neurofilament light and others)Blood tests for CJD (plasma or serum neurofilament light and total tau) discriminate CJD from other dementias with an AUC of about 0.93 in one series,
- Blood prion seed amplification assays (RT-QuIC and PMCA in blood)This entity covers the class of tests that look for misfolded prion protein itself in blood, by amplifying it in a tube, rather than measuring damage markers.
- CSF 14-3-3 and total tauCSF 14-3-3 and total tau are older surrogate markers of rapid neuronal damage that support a CJD diagnosis: about 85 to 86 percent sensitive in sporad
- CSF PrP quantification (ELISA and mass spectrometry)CSF PrP quantification measures total prion protein in spinal fluid.
- EP-QuIC (endpoint quaking-induced conversion, CSF), Canadian accredited assayDetects: seeding activity of misfolded prion protein.
- ES-QuIC (enhanced sensitivity endpoint QuIC, deer mouse substrate)Detects: seeding activity of misfolded prion protein.
- MRI and EEGBrain MRI (cortical and basal ganglia diffusion signal) and EEG (periodic sharp wave complexes) are the widely available first-line tests in CJD crite
- Nano-QuIC (silica nanoparticle enhanced RT-QuIC, University of Minnesota and Priogen)Nano-QuIC is a modified RT-QuIC seed amplification test in which silica nanoparticles, about 50 nm across in the first paper, are added to the reactio
- Olfactory mucosa (nasal brushing) RT-QuICRT-QuIC on a nasal brushing (olfactory mucosa) is a minimally invasive prion test: 97 percent sensitive and 100 percent specific in a 2014 NEJM study,
- Paraffin-embedded tissue blot (PET blot) for prion and alpha-synuclein aggregatesThe PET blot is a tissue method for showing where proteinase resistant, aggregated prion protein sits in a section of brain or other tissue.
- MRC Prion Unit direct detection assay (solid-state capture and immunodetection of disease-associated PrP in blood and urine)The direct detection assay (DDA) is a non-amplification prion test built at the MRC Prion Unit at UCL.
- PRNP gene sequencing (diagnostic and predictive)PRNP sequencing reads the prion protein gene in DNA from blood, saliva, a cheek swab or autopsy tissue.
- CSF RT-QuIC (second generation)Detects: Seeding activity of misfolded prion protein.
- RT-QuIC with recombinant human PrP E219K substrate for human prion strain discriminationThis is a laboratory method, not a service.
- Skin punch biopsy RT-QuICRT-QuIC on a skin punch biopsy detects prion seeding with about 89 percent sensitivity in one 71-sample series; sensitivity varies by strain and sampl
- Surf-PMCA, amplification test for variant CJD prions on steel surfaces used to evaluate decontamination (EFS TransDiag, Montpellier)Surf-PMCA is a laboratory test, not a patient test.
- Tear fluid RT-QuICRT-QuIC on tear fluid (a Schirmer strip) is a non-invasive prion test from the Goettingen group: 16 of 19 patients positive and 94 of 94 other neurolo
- Urine prion seed amplification (PMCA) testUrine PMCA is a research laboratory method that looks for the misfolded prion protein (PrPSc) in urine by concentrating the sample and then amplifying
- Plasma prion amplification test for variant CJD (EFS blood service with the Paris Brain Institute, 2016)A research blood test for variant CJD developed by the French national blood service (Etablissement Francais du Sang, EFS) at its TransDiag laboratory