A second way of estimating kidney filtration, using a protein whose blood level does not depend on how much muscle you carry. That matters in exactly the people longevity clinics attract: in a very muscular adult a creatinine-based eGFR reads falsely low, and in a frail or sarcopenic one it reads falsely reassuring. Cystatin C is the tie-breaker, not the first test.
Shlipak MG, Matsushita K, et al. “Cystatin C versus creatinine in determining risk based on kidney function.” N Engl J Med 2013;369:932–943 pooled 11 general-population cohorts totalling 90,750 participants and found that an eGFR based on cystatin C strengthened the association between kidney function and both death and end-stage renal disease, reclassifying a substantial share of people labelled with CKD by creatinine alone. KDIGO accordingly recommends cystatin C as a confirmatory test when a creatinine-based eGFR falls in the uncertain 45–59 range with no other marker of kidney damage — a defined, selective use rather than a blanket screen.
Shlipak MG, et al. N Engl J Med. 2013. PubMed: PMID 24004120
Singapore guidance
Not covered in the current review
Singapore’s national screening committee has not reviewed this test in the current volume of its report, which covers nine conditions. That is not a verdict either way.
Source: Screening Test Review Committee report 2026, Volume 1 (Academy of Medicine Singapore and Ministry of Health, February 2026). The full national list · How this is used.
What you would actually pay
- Healthier SG
- Not subsidised
- MediSave
- Not among the screenings named for outpatient claims
Source: Healthier SG Screening (HealthHub) and MediSave outpatient care (Ministry of Health). Absence from either list is not a statement that the test is discouraged — only that no subsidy or claim applies. Gross prices compared.
What it costs when it is wrong
- Basis
- No published harm criterion found
- Severity
- Not documented
Not covered in the current volume of the committee’s report, so no harm criterion was found either way.
An empty finding, not a clean bill of health: this means nothing documented was found for this test. It is not a claim that the test is safe.
Screening harm is not only a laboratory question: the committee’s own criteria advise against a test when “the screening test, or follow-up tests arising from a positive screen, are associated with significant medical risks”. Sources on overdiagnosis → · How this is graded.
FAQ
Is the Cystatin C worth doing in Singapore?
Cystatin C carries a moderate evidence grade for screening adults without symptoms. It typically costs S$40–70 in Singapore. The usual schedule: once, to confirm or refute a borderline creatinine-based eGFR. Most appropriate for adults with an eGFR of 45–59 and no other evidence of kidney damage; anyone whose muscle mass makes creatinine misleading.
Weighing this against something else? Compare it with two other tests → · Price it inside a panel →