Annual blood test: which tests do you actually need?

More people are getting annual blood tests, and for good reason. Blood work can detect abnormalities long before symptoms appear: elevated cholesterol, early iron deficiency, a thyroid slowly going out of balance. But with dozens of markers and varying packages available, it can be difficult to determine what you actually need. This guide helps you make an informed choice.

Why test annually?

Regular blood testing offers three key benefits. First, prevention: many conditions like high cholesterol, type 2 diabetes and anaemia develop gradually over years. Early detection means early intervention, when lifestyle changes can still make the difference. Second, trend recognition: a single measurement is a snapshot. The real value emerges when you compare multiple results over the years. A cholesterol that rises a little each year tells a different story than a one-time borderline result. Third, early signals: your body often gives subtle warnings through blood values long before you notice anything. A declining haemoglobin, a rising HbA1c or a shifting TSH can precede symptoms by months or even years.

Essential tests for everyone

Regardless of age or background, these tests form a solid foundation for an annual health check.

Complete blood count

Screens for anaemia, infections, inflammation and clotting issues. Haemoglobin is the core value for anaemia, while MCV indicates the likely cause (low MCV points to iron deficiency, high MCV to B12 or folate deficiency). A haemoglobin at the lower end of normal can already noticeably affect your energy and endurance.

Cholesterol panel

Cardiovascular disease is the leading cause of death in the Netherlands. LDL cholesterol is the primary predictor of cardiovascular risk and the target for treatment. Elevated cholesterol causes zero symptoms while arteries gradually narrow, making it a textbook example of a value you simply cannot know without testing.

Blood sugar (HbA1c)

HbA1c reflects your average blood sugar over the past 2-3 months. Below 42 mmol/mol is normal. 42-48 indicates prediabetes, the window where lifestyle changes can still prevent diabetes. Above 48 indicates diabetes. An estimated 1 million people in the Netherlands have prediabetes without knowing it.

Liver and kidney function

ALAT is the most sensitive marker for liver cell damage and can detect fatty liver disease when you are completely symptom-free. An estimated 25-30% of the Dutch population has some degree of fatty liver. Creatinine and eGFR assess kidney function. Both organs rarely produce symptoms with mild dysfunction, making blood testing the only way to catch problems early.

Thyroid function (TSH)

TSH is the go-to screening value for thyroid problems, which affect an estimated 5-10% of the population. Thyroid symptoms are notoriously vague: fatigue, weight change, mood swings, hair loss, concentration problems. Many people attribute these to stress or ageing. A single TSH measurement can save months of diagnostic uncertainty.

Additional tests by age group

• 20-35 - iron status (ferritin, especially menstruating women, as it drops long before haemoglobin does), vitamin D (surprisingly common deficiency in the Netherlands), STI screening if relevant.
• 35-50 - extended lipid panel (ApoB, lipoprotein(a)) if family history of cardiovascular disease, HbA1c becomes increasingly important, expanded liver values (ALAT + ASAT + gamma-GT, fatty liver peaks in this age group), vitamin B12 if vegetarian, vegan or on acid suppressants.
• 50+ - expanded kidney function (microalbumin if diabetic or hypertensive), inflammation markers (hs-CRP if elevated cardiovascular risk), bone health (calcium, vitamin D, ALP for osteoporosis risk), PSA for men (a personal decision in consultation with your GP), vitamin B12 (absorption declines with age).

Additional tests by risk profile

• Family history of cardiovascular disease - ApoB, lipoprotein(a) (genetically determined, only needs to be measured once), hs-CRP in addition to standard cholesterol.
• Overweight - annual HbA1c, ALAT, lipid panel and fasting glucose as a minimum. Fatty liver occurs in 60-80% of people with overweight and is fully reversible in early stages.
• Chronic stress - TSH (thyroid is sensitive to chronic stress effects), vitamin D, magnesium (stress increases magnesium consumption), ferritin (iron deficiency and stress share many symptoms), complete blood count.
• Vegetarian/vegan diet - vitamin B12 (deficiency develops slowly but can cause partly irreversible neurological damage), ferritin (plant-based iron is less efficiently absorbed), zinc, vitamin D.
• Intensive athletes - complete blood count (distinguish sports anaemia from true anaemia), ferritin (common deficiency in endurance athletes), magnesium (loss through sweat), vitamin D (especially indoor athletes).

Tips for reliable results

The conditions under which you have blood drawn directly affect the results. Key recommendations:

• Schedule before 10:00 AM, fasted for 8-12 hours (water is fine and recommended)
• Avoid alcohol for at least 48 hours (affects liver values and triglycerides)
• No intense exercise the day before (affects ASAT, CK, leukocytes and haematocrit)
• Report all medications and supplements to your healthcare provider
• If on levothyroxine, take it after the blood draw
• Stop biotin supplements 48 hours before (interferes with multiple lab tests, especially thyroid values)
• Stay well hydrated (dehydration artificially elevates haemoglobin, haematocrit and proteins)

Frequently asked questions

How often should I test if healthy?

Annual testing is a good frequency for most adults. Under 30 without symptoms or risk factors, every 2 years may suffice. With risk factors (family history, overweight, smoking), annual testing is recommended. With chronic conditions or medication, your doctor determines the frequency.

Does insurance cover annual blood work?

If requested by your GP for a medical indication, it typically falls under basic insurance (after the deductible). Preventive testing on your own initiative is usually not covered by basic insurance. Some supplementary policies include a preventive health check budget. Check your policy or contact your insurer.

Can I test too often?

There is no medical objection to regular testing. However, more than twice a year for healthy people is usually unnecessary and may cause worry over normal biological variation. Blood values are not identical from day to day. Exceptions apply for chronic conditions, recently started medication or active treatment plans.

What if my results are abnormal?

An abnormal result is not automatically a diagnosis. It is a signal that deserves attention. For mild abnormalities, a repeat test after 4-6 weeks may suffice. For clear abnormalities, we always recommend contacting your GP for a targeted next step. You can bring your Vital Check results to your GP appointment.