When and how is sarcopenia diagnosed?

Sarcopenia is challenging to diagnose and requires a combination of clinical tests that measure muscle mass, performance, and strength to identify the disease and its severity.1 Although people can experience muscle decline at any age, healthcare providers typically start testing for sarcopenia after the age of 65. For this reason, sarcopenia is believed to be underdiagnosed.2

Walking (Gait) Speed: The gait speed test measures the time it takes for a person to travel a specified distance at their normal walking pace. According to the criteria from the European Working Group on Sarcopenia in Older People (EWGSOP2), a gait speed of ≤0.8 m/s (over a 4-meter walking distance) suggests low muscle performance and may indicate sarcopenia.3

Sit-to-Stand Test: The sit-to-stand test is used to determine leg muscle strength by timing how long it takes a person to stand up from a seated position five times in a row without using their arms. Taking longer than 15 seconds to complete the task is common in those with low muscle strength.4 Similar tests count the number of times a person can repeatedly sit and stand from a chair without the use of their arms within a 30 second timeframe. Men completing 17 or fewer stands and women completing 15 or fewer stands within 30 seconds suggests sarcopenia.3

Short Physical Performance Battery (SPPB) Test: SBBP includes a combination of three timed tasks including sit-to-stand, standing balance, and walking speed. Individuals are scored on a scale of 0 (worst performance) to 12 (best performance), where an SPPB score ≤8 suggests poor balance and reduced physical performance.4

Grip Strength: According to the Sarcopenia Definitions and Outcomes Consortium (SDOC), grip strength is an important discriminator of mobility disability and a predictor of health-related outcomes. The test is performed with a calibrated handheld device called a dynamometer. Individuals are told to squeeze the dynamometer as hard as they can while seated with elbows at a 90° angle. The cut-off values for low grip strength vary by guideline, ranging from less than 27–35.5 kg for men and less than 16–20 kg for women.4–6

Dual-Energy X-ray Absorptiometry (DEXA/DXA): The DEXA scan is a non-invasive imaging technique that uses low-energy X-rays to measure whole-body composition including muscle mass, fat mass, and bone density. The key thresholds for sarcopenia are a lean mass index of <7.0 kg/m2 for men and <5.4 kg/m2 for women.1

Bioelectrical Impedance Analysis (BIA): BIA estimates body composition based on tissue conductivity of a small, alternating electrical current.7 Fat tissue is more resistant to the flow of electrical current than muscle tissue because of its lower water and electrolyte content. Based on the resistance of the current, physicians can estimate the relative levels of fat, muscle, and water in the body. Like the DEXA/DXA scan, the relative amounts of muscle can help determine whether someone has sarcopenia, where a lean mass index of <7.0 kg/m2 for men and <5.7 kg/m2 for women is a strong indicator.1

 

Taken together, incorporating DEXA and BIA scan-derived cut-offs for muscle mass with scores from functional muscle tests allows for a more accurate assessment of sarcopenia risk. A multimodal approach for sarcopenia diagnosis ensures that both quantitative changes in muscle tissue and functional decline are identified, which can help improve early detection and intervention.

Additional Resources

  1. Voulgaridou, G. et al. Diagnostic Criteria and Measurement Techniques of Sarcopenia: A Critical Evaluation of the Up-to-Date Evidence. Nutrients 16, 436 (2024).

  2. Damanti, S. et al. Acute Sarcopenia: Mechanisms and Management. Nutrients 16, 3428 (2024).

  3. Sawada, S. et al. The 30-s chair stand test can be a useful tool for screening sarcopenia in elderly Japanese participants. BMC Musculoskelet. Disord. 22, 639 (2021).

  4. Cruz-Jentoft, A. J. et al. Sarcopenia: revised European consensus on definition and diagnosis. Age Ageing 48, 16–31 (2019).

  5. Chen, L.-K. et al. Asian Working Group for Sarcopenia: 2019 Consensus Update on Sarcopenia Diagnosis and Treatment. J. Am. Med. Dir. Assoc. 21, 300-307.e2 (2020).

  6. Bhasin, S. et al. Sarcopenia Definition: The Position Statements of the Sarcopenia Definition and Outcomes Consortium. J. Am. Geriatr. Soc. 68, 1410–1418 (2020).

  7. Foster, K. R. & Lukaski, H. C. Whole-body impedance--what does it measure? Am. J. Clin. Nutr. 64, 388S-396S (1996).