Quinke's Sign Reliability in Assessing Cardiac Function
Quinke's sign (capillary pulsation in the nailbed) is not useful for assessing cardiac function and should not be relied upon clinically. 1
Evidence Against Clinical Utility
The most definitive research examining Quinke's sign concluded it lacks clinical utility for diagnosing or assessing aortic insufficiency, despite its historical association with this condition. 1 This finding is particularly important because:
- The sign appears in many normal individuals, making it non-specific for pathology 1, 2
- It can be mimicked by non-cardiac conditions such as sclerodactyly and keratoderma, where mechanical compression of nailbeds creates visible pulsations without any underlying hemodynamic abnormality 2
- No sensitivity or specificity data support its use, unlike other peripheral signs of aortic regurgitation 1
Superior Alternative Physical Examination Signs
When evaluating for aortic insufficiency specifically, the evidence supports using different physical examination findings:
- Duroziez's sign (femoral double intermittent murmur, as modified by Blumgart and Ernstene) demonstrates approximately 100% specificity and 90% sensitivity for aortic insufficiency, making it highly recommended 1
- Hill's sign (popliteal systolic blood pressure exceeding brachial systolic pressure by ≥20 mmHg) can predict the severity of aortic insufficiency and correlates with angiographic findings, though it misses mild cases 1
- De Musset's sign (head bobbing) has undetermined but apparently low sensitivity and specificity 1
Context of Physical Examination Reliability
The limitations of Quinke's sign fit within broader evidence about physical examination reliability:
- Physical signs in general demonstrate significant interobserver variability, with physicians achieving complete agreement only 55% of the time when examining the same patients 3
- Even vital sign measurements show substantial variability, with expected ranges of agreement for blood pressure of ±24.2 mmHg systolic and ±19.9 mmHg diastolic between trained observers 4
Recommended Approach for Cardiac Assessment
For evaluating cardiac function, echocardiography remains the gold standard rather than relying on peripheral physical signs. 5 Echocardiography provides:
- Direct visualization of valve function and regurgitation 5
- Quantitative assessment of ventricular function 5
- Hemodynamic measurements including pressure gradients 5
- Assessment of right ventricular function and pulmonary pressures 5, 6
When aortic insufficiency is suspected clinically, proceed directly to echocardiographic evaluation rather than attempting to confirm with unreliable peripheral signs like Quinke's pulse. 1