The phrase implies a list of tests(baseline nutritional assessment) to request. The evidence points somewhere different, and the correction is worth making before anything else.
Routine nutrient screening in average-risk adults is not recommended. What’s recommended instead is narrower, cheaper, and mostly already sitting in a drawer.
The correction first
Taking vitamin B12 as the worked example, since it’s the nutrient most often proposed for a baseline panel:
Screening average-risk adults for vitamin B12 deficiency is not recommended. Screening may be warranted in patients with one or more risk factors[2].
And more pointedly: no major medical organisation, including the US Preventive Services Task Force, has published guidelines on screening asymptomatic or low-risk adults for B12[4].
The threshold suggested instead is specific. Testing should be considered in patients with at least one risk factor for and one clinical feature of deficiency[1].
Both, not either.
This isn’t a claim that testing is useless. It’s that a panel ordered without indication generates results that require interpretation, and interpretation of an unindicated result is where over-treatment starts.
What you already have
Before adding anything, the more useful move is looking at what exists.
Korea’s national health screening already produces, as covered in an earlier post: fasting glucose, haemoglobin, liver enzymes, serum creatinine, urine protein, and — for women from 40, every four years — a full lipid panel.
That’s five nutrition-relevant values plus lipids, arriving on a schedule, at no cost, for anyone enrolled in the national insurance system.
The most common failure isn’t a missing test. It’s a result that arrived, got filed, and was never read against the previous one.
Direction matters more than any single value. That’s a theme running through this entire series — haemoglobin falls last in iron depletion, a single hormone reading can’t stage the menopausal transition, one bone density number doesn’t map neatly onto fracture risk. In each case, the trend carries information the snapshot doesn’t.
Two result sheets side by side are worth more than a third test.
Where the real gaps are
Two nutrients relevant to this readership genuinely aren’t in the standard panel.
Vitamin D. Not part of Korea’s national screening, as noted in the screening post. Given that deficiency is common here and that vitamin D’s role becomes load-bearing precisely when calcium intake is low — the subject of the calcium absorption post — this is a defensible thing to ask about rather than assume.
Ferritin. Haemoglobin is measured; iron stores are not. And as the anemia post covered, ferritin falls first and haemoglobin last. A normal haemoglobin doesn’t establish adequate stores.
Neither of these means “get tested.” It means these are the two worth raising if there’s a reason to.
Who has an actual indication
Risk-based testing means the question is whether you’re in a defined group. For B12, the recognised risk factors are specific[2]:
- Metformin use for more than four months
- Proton pump inhibitors or H2 blockers for more than 12 months
- Gastric or small intestine resection
- Inflammatory bowel disease
- Vegan or strict vegetarian diet
- Adults older than 75
The prevalence data show why these matter.
| Population | Prevalence |
| Under 60 (US/UK) | ~6% |
| Over 60 (US/UK) | ~20% |
| Metformin-treated adults aged 65+ | 29.4% |
[Table 1] Vitamin B12 deficiency prevalence by group · Source: related research[2][3][5]
Note the two medication entries. Metformin and acid-suppressing drugs are extremely common, taken long-term, and neither is intuitively connected to a nutrient problem — which is exactly why the association is worth knowing.
A retrospective review recommended that physicians consider screening patients on metformin who are over 65 and have used it for more than five years[5].
The test has limits too
One more thing, consistent with everything else in this series.
Measurements of serum vitamin B12 may not reliably detect deficiency[4]. In asymptomatic high-risk patients with low-normal levels, methylmalonic acid or homocysteine is needed to confirm[1][4].
This is the same shape of problem we’ve seen repeatedly: ferritin misleading in the presence of inflammation, calculated LDL running low in Korean populations, a screening dipstick with 56% specificity. The number arrives looking definitive and isn’t.
Which is another argument against unindicated panels. A borderline result on a test you didn’t need generates a second test, and possibly a third.
What to actually do
Five steps, in descending order of value.
- Collect what you already have. Screening results from the past several years, in one place. This costs nothing and is the highest-yield action available.
- Look at direction, not just values. Two or three years of the same measure tells you something a single reading cannot.
- Check whether you’re in a risk group. Long-term metformin, long-term acid suppression, restricted diet, over 75, prior gut surgery. If yes, that’s an indication worth raising.
- Bring your supplement list. As covered in the interactions post, the containers themselves are more reliable than memory — and what you’re already taking changes which results matter.
- Ask what’s worth adding, rather than requesting a panel. The clinician has your history. A general request produces a general answer.
And the framing to carry into that conversation: the question isn’t “how are my levels,” it’s “is anything actually short.” Those sound similar and lead to different places — one toward optimisation, the other toward correction. This series has consistently found evidence supporting the second and not the first.
Closing
I set out expecting to assemble a recommended panel and found the literature pointing the other way.
No major body recommends routine nutrient screening in average-risk adults. The suggested threshold for B12 — the most commonly proposed addition — is one risk factor and one clinical feature. Not curiosity, not thoroughness.
What that leaves is less exciting and more useful. Most of the relevant values already arrive through national screening and go unread. The two genuine gaps are worth raising only if there’s a reason. And the risk factors that do warrant testing are mostly medications people are already taking without connecting them to nutrition.
The honest baseline assessment, then, is mostly an act of retrieval rather than acquisition.
At a Glance
- Routine nutrient screening in average-risk adults is not recommended by any major body
- For B12, testing is suggested with one risk factor AND one clinical feature
- Korea’s national screening already provides glucose, haemoglobin, liver enzymes, creatinine, urine protein and a lipid panel for women from 40
- Direction over time carries more information than a single value
- The genuine gaps for this readership are vitamin D and ferritin — neither is in the standard panel
- B12 risk factors include metformin over four months and acid suppressants over 12 months
- Prevalence: ~6% under 60, ~20% over 60, 4% in metformin-treated adults 65+
- Serum B12 may not reliably detect deficiency — MMA or homocysteine confirms in borderline cases
※ This article is for general information and does not replace medical advice. It is not a recommendation to obtain any specific test — testing decisions depend on individual history and belong with a clinician. Do not interpret laboratory values on your own, and do not start, stop or adjust supplements or medication based on a result you have read yourself.
References
- “Vitamin B12 Deficiency: Common Questions and Answers”, American Family Physician 2025 (risk factor plus clinical feature threshold; diagnostic cutoff), https://www.aafp.org/afp/2025/0900/vitamin-b12-deficiency
- Langan RC, Goodbred AJ. “Vitamin B12 Deficiency: Recognition and Management”, American Family Physician 2017 (screening not recommended in average-risk adults; risk factor list; prevalence by age), https://www.aafp.org/pubs/afp/issues/2017/0915/p384.html
- “Vitamin B12 deficiency in metformin-treated community-dwelling older adults with diabetes: A cross-sectional multicentre study”, PMC, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12789806/
- “Update on Vitamin B12 Deficiency”, American Family Physician (absence of USPSTF guidance; limits of serum B12 measurement), https://www.aafp.org/pubs/afp/issues/2011/0615/p1425.html
- “Assessment of vitamin B12 deficiency and B12 screening trends for patients on metformin: a retrospective cohort case review”, PubMed, https://pubmed.ncbi.nlm.nih.gov/34308109/