Diagnostic accuracy
Smartphone PPG to detect atrial fibrillation
Open access · cc by · source: Europe PMC
FibriCheck PPG showed ~96% sensitivity and specificity versus cardiologist ECG on analysable traces.
Study at a glance
- Design
- Cross-sectional — Diagnostic accuracy vs 12-lead ECG in primary care
- N
- N=223 · 241 enrolled; 223 analysed after exclusions
- Population
- Primary-care patients screened for atrial fibrillation with FibriCheck PPG
- Outcome
- Sensitivity and specificity of mobile PPG for AF vs 12-lead ECG
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
241 enrolled; 223 analysed. Sensitivity 95.6%, specificity 96.6% vs ECG.
Methodology
Primary-care patients underwent FibriCheck PPG and 12-lead ECG; accuracy calculated after excluding pacing and poor signals.
Limitations
Needs adequate signal quality; pacing excluded; PPV/NPV depend on prevalence.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
Phone pulse waveforms can detect atrial fibrillation accurately versus ECG in clinic samples.
Smartphone photoplethysmography detected atrial fibrillation with sensitivity about 95.6% and specificity about 96.6% versus ECG in an analysed clinic sample (adequate signal required; pacing excluded).
Evidence for the claim as stated.
A multiplex assay can identify Staphylococcus from blood cultures with very high accuracy.
A multiplex molecular assay on monomicrobial blood cultures identified Staphylococcus at genus level with sensitivity about 99.4% and specificity about 99.7% in a large evaluated set.
Scope note — different modality — PPG AF screening, not microbiology ID
Limits the claim's scope: a different population, assay, or outcome.
In GP care, CA125 looks accurate but a positive rarely means ovarian cancer when disease is rare.
In GP care, CA125 ≥35 U/ml for ovarian cancer showed sensitivity about 77%, specificity about 93.8%, and AUC about 0.92, but PPV was only about 10.1% because incidence was about 0.9%—illustrating prevalence’s grip on predictive value.
Scope note — higher-prevalence clinic AF sample — PPV/NPV not transportable as raw sensitivities
Limits the claim's scope: a different population, assay, or outcome.
Higher blood GFAP and NfL associate with later dementia risk — prognosis, not same-day diagnosis.
In UK Biobank, higher baseline plasma GFAP and NfL were associated with roughly doubled hazards of incident dementia over ~13 years, with incremental discrimination when added to demographic risk scores—prognostic biomarker performance, not a bedside diagnostic rule-in test.
Scope note — different task — detecting current AF vs ECG, not forecasting dementia
Limits the claim's scope: a different population, assay, or outcome.
Point-of-care classification accuracy (AF, blood culture ID, sickle cell, pain subtype) is not the same claim as low-prevalence screening PPV or long-horizon prognostic discrimination. Mixing sensitivities with hazards or PPVs invents a false head-to-head.
Evidence for the claim as stated.
High sensitivity/specificity in a selected clinic sample does not guarantee useful predictive values in a low-prevalence screening population—the CA125 GP analysis is the cautionary case in this library.
Evidence for the claim as stated.
Primary-care FibriCheck PPG, after excluding pacing and poor signals, classified atrial fibrillation against 12-lead ECG with sensitivity 95.6% and specificity 96.6% (241 enrolled, 223 analysed). Signal quality is a prerequisite; PPV and NPV still depend on prevalence in the waiting room being tested.
Evidence for the claim as stated.
The five papers are tuned to different prevalences and harms of error, so a 'good' sensitivity/specificity pair is not portable. CA125's 77%/93.8% at 0.9% incidence yields PPV 10.1% — a primary-care rare-disease problem. StEP's 95%/93% pinprick figures come from specialist clinics where neuropathic pain is common. FibriCheck's 95.6%/96.6% is versus ECG after dropping poor signals. Blood-culture 99.4%/99.7% is laboratory identification, not community screening. Frailty's 99.1% specificity describes a ~1.1% trajectory class, not a test you run on everyone.
Evidence for the claim as stated.
FibriCheck PPG was compared with 12-lead ECG in primary care (241 enrolled, 223 analysed), yielding sensitivity 95.6% and specificity 96.6% after excluding pacing and poor signals. That is agreement with a reference standard, not a blinded placebo-controlled treatment trial. PPV and NPV still depend on prevalence.
Evidence for the claim as stated.
Who is blinded, and whether a placebo exists, disagrees across the four papers. SEPP blinded the collector while comparing an identifiable parenting programme with standard care. Partners PrEP adherence work sits inside a placebo-controlled antiretroviral trial but reports UPC/MEMS adherence (99.1%/97.2%), not a placebo-subtracted efficacy estimate. The child-care zBMI trial is an open cluster-style programme contrast. FibriCheck does not assign a treatment at all. One method label is doing four jobs.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
Point-of-care classification accuracy (AF, blood culture ID, sickle cell, pain subtype) is not the same claim as low-prevalence screening PPV or long-horizon prognostic discrimination. Mixing sensitivities with hazards or PPVs invents a false head-to-head.
High sensitivity/specificity in a selected clinic sample does not guarantee useful predictive values in a low-prevalence screening population—the CA125 GP analysis is the cautionary case in this library.
The five papers are tuned to different prevalences and harms of error, so a 'good' sensitivity/specificity pair is not portable. CA125's 77%/93.8% at 0.9% incidence yields PPV 10.1% — a primary-care rare-disease problem. StEP's 95%/93% pinprick figures come from specialist clinics where neuropathic pain is common. FibriCheck's 95.6%/96.6% is versus ECG after dropping poor signals. Blood-culture 99.4%/99.7% is laboratory identification, not community screening. Frailty's 99.1% specificity describes a ~1.1% trajectory class, not a test you run on everyone.
- Supports · How well does CA125 find ovarian cancer in GP care?
- Supports · StEP pain-subtype assessment
- Supports · Rapid gram-positive blood culture ID
- Supports · Rising frailty flags one-year death risk
Who is blinded, and whether a placebo exists, disagrees across the four papers. SEPP blinded the collector while comparing an identifiable parenting programme with standard care. Partners PrEP adherence work sits inside a placebo-controlled antiretroviral trial but reports UPC/MEMS adherence (99.1%/97.2%), not a placebo-subtracted efficacy estimate. The child-care zBMI trial is an open cluster-style programme contrast. FibriCheck does not assign a treatment at all. One method label is doing four jobs.
- Supports · Tech parenting program cut postpartum distress
- Supports · PrEP adherence in Partners PrEP
- Supports · Child-care diet/activity RCT and zBMI
History
When this study was placed
Dated entries from the concept change log — when this paper was added or removed as support, challenge, or qualifier on a claim.
Placed as a scope qualifier on Diagnostic Accuracy
A multiplex molecular assay on monomicrobial blood cultures identified Staphylococcus at genus level with sensitivity about 99.4% and specificity about 99.7% in a large evaluated set.
Placed as a scope qualifier on Diagnostic Accuracy
In GP care, CA125 ≥35 U/ml for ovarian cancer showed sensitivity about 77%, specificity about 93.8%, and AUC about 0.92, but PPV was only about 10.1% because incidence was about 0.9%—illustrating prevalence’s grip on predictive value.
Placed as a scope qualifier on Diagnostic Accuracy
In UK Biobank, higher baseline plasma GFAP and NfL were associated with roughly doubled hazards of incident dementia over ~13 years, with incremental discrimination when added to demographic risk scores—prognostic biomarker performance, not a bedside diagnostic rule-in test.
Placed as supporting evidence on Diagnostic Accuracy
High sensitivity/specificity in a selected clinic sample does not guarantee useful predictive values in a low-prevalence screening population—the CA125 GP analysis is the cautionary case in this library.
Related papers in this topic
Same topic cluster — not a recommendation engine.