Measurement · not graded
REMS Ultrasound Bone Densitometry
What the evidence looks at: agreement with DXA bone density, and whether the result reflects the bone or the inputs.
At a glance
A REMS scan uses ultrasound, with no radiation, to estimate bone density at the hip and spine. This page asks how well it matches a DEXA scan, the standard test. Large studies found close agreement. Two newer studies found that the result depended mostly on the age and weight typed into the machine. It measures bone, and it does not treat it.
What the studies looked at: Agreement with DXA bone density, and whether the result reflects the bone or the inputs
Why this letter
Ungraded: REMS measures bone, it does not treat anything. The letters on this site belong to interventions; a bone density result is information, and what is done about it is graded on its own record.
In a European multicenter series it classified osteoporosis with about 90 percent sensitivity and 95 percent specificity against DXA (PMID PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed. 33278653), and across 17 studies its values correlated with DXA at about 0.8 (PMID 41651205). Two independent 2026 studies found the result driven mostly by the age and weight typed into the machine (PMID 41872364, PMID 42442525), and in a small longitudinal cohort its year-to-year changes did not track DXA's (PMID 41951808). A one-time screen is where the evidence is strongest; following change over time is where it is weakest.
Evidence notes: Device-validation studies (measurement accuracy)
Last reviewed: October 2026
Dose, form and timing
Same device and the same correctly entered age, weight and height for every scan, since those inputs move the result (PMID 41872364). A REMS result and a DXA result are not interchangeable and are not compared with each other as a change over time.
Grade history
How this letter has changedLatest: No. 341 · October 2026 · Corrected.
REMS bone scans were sold direct to consumers at a longevity conference, so they now have a record. Like DEXA, the scan is a measurement and carries no letter. Cortet et al. (Bone, 2021; PMID 33278653) found it classified osteoporosis close to DXA, and Chan et al. (Osteoporos Int, 2026; PMID 41872364) found the typed-in age and weight explained most of its result.PMID 33278653 PMID 41872364
Every change to a letter on this site is dated and published. The full evidence log →
Sources
Primary evidenceFive papers, each linked to its PubMed record.
Cortet et al. (Bone, 2021; PMID 33278653): European multicenter study, 4,245 lumbar spine and 4,271 femoral neck scans in women; against DXA, osteoporosis was identified with 90.4 percent sensitivity and 95.5 percent specificity at the femoral neck. A 2026 meta-analysis A study that pools the numbers from several trials into one combined estimate. (Bone; PMID 41651205): 17 studies, over 7,000 people, 90 percent women; correlation with DXA 0.82 at the femoral neck and 0.77 at the spine, with very high heterogeneity How much the results of the pooled trials differ from each other. High heterogeneity makes a combined estimate less reliable. and weaker agreement in disease groups. Chan et al. (Osteoporos Int, 2026; PMID 41872364): typed-in age and weight explained over 90 percent of the variation in REMS bone density; in volunteers whose bone did not change, adding a decade to the age input lowered the femoral neck result about 6.3 percent and adding 5 kg to the weight input raised it about 4.3 percent. An Australian real-life study (Bone, 2026; PMID 42442525): 69 patients; REMS and DXA could not be used interchangeably, and age and weight explained most of the REMS result but only a third of DXA's. Diz Lopes et al. (Osteoporos Int, 2026; PMID 41951808): 20 peritoneal dialysis patients over about 20 months; DXA detected femoral neck loss that REMS did not, and annual changes did not correlate. Ungraded: measurement validity, not a treatment claim.
Disclosure
Educational use only · Not medical advice · EBL grades published human evidence and does not recommend treatment.
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