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Health Check

Glucose (blood sugar) – Blood sugar right now

Glucose, or blood sugar, shows how much sugar is present in the blood at the moment the sample is taken. The test is usually taken as fasting glucose after at least eight hours without food, and is included in most broad health checks to detect elevated blood sugar, prediabetes and diabetes.

What is Glucose (blood sugar)?

Glucose is the body's main fuel and comes mainly from carbohydrates in food. The level in the blood is regulated by the hormone insulin, which helps cells absorb the sugar. A fasting glucose test measures blood sugar after an overnight fast, while a non-fasting glucose test is taken regardless of meals and therefore varies more.

Why is Glucose (blood sugar) measured in a health check?

Elevated blood sugar often develops over a long time without clear symptoms. A blood test with fasting glucose in a health check is a simple way to catch early insulin resistance, prediabetes or diabetes before damage occurs to blood vessels, kidneys or eyes.

High and low values

High value: High values can suggest reduced insulin sensitivity, prediabetes or diabetes, but can also be due to stress, an ongoing infection, or not having fasted before the test. A single high value should always be followed up with a repeat test and preferably HbA1c.

Low value: Low values can be due to prolonged fasting, intense physical exertion shortly before the test, or in some cases diabetes medication. Symptoms of low blood sugar include shakiness, cold sweats, palpitations and difficulty concentrating.

Reference ranges differ between laboratories, sexes and ages and are stated in your result. The information here does not replace medical assessment.

How is a glucose test taken in a health check?

Fasting glucose is taken as a standard venous blood sample, usually from the crook of the arm, alongside the rest of the health check. Fasting means avoiding food, sweetened drinks, chewing gum and snus for at least eight hours before the test, while plain water is allowed. Most people book a morning appointment after fasting overnight, since this is both the simplest option and gives a result that's easy to interpret.

Health checks that include both fasting glucose and blood lipids require the same fasting for all tests, so one visit is enough. If you've accidentally eaten or drunk something other than water before the test, mention it, since a non-fasting value is interpreted differently from a fasting glucose result.

Who should check their blood sugar?

Type 2 diabetes often develops gradually over several years without clear symptoms until blood sugar is already significantly elevated. A blood test in a health check is therefore one of the simplest ways to catch a disturbance early, before it affects blood vessels, kidneys, eyes or nerves.

  • People who are overweight, especially with abdominal fat
  • Those with a family history of diabetes
  • People with high blood pressure or high blood lipids
  • Those with a sedentary lifestyle or little physical activity
  • Women who have had gestational diabetes
  • People with recurrent infections, blurred vision, increased thirst or frequent urination

How does glucose differ from HbA1c?

Fasting glucose and HbA1c measure blood sugar in different ways and complement each other in a health check. Fasting glucose shows how much sugar is in the blood at the exact moment the sample was taken, after an overnight fast. The value can therefore vary from day to day depending on what you ate the night before, how you slept, or whether you were stressed. HbA1c, described in more detail on its own page, instead measures what proportion of the haemoglobin in the blood has sugar bound to it, reflecting an average over the last two to three months since red blood cells live for about that long.

A single fasting glucose test can therefore miss someone whose blood sugar is only elevated at certain times or after meals, while HbA1c captures the overall picture over time. On the other hand, fasting glucose reacts more quickly to changes and is therefore often used to confirm or follow up an abnormal HbA1c. In a broad health check it's common for both tests to be taken together, since combined they give a more reliable assessment than either alone.

What doesn't a single glucose value show?

A single fasting glucose result says nothing about how blood sugar fluctuates during a normal day, for example after meals, under stress, or with lack of sleep. It also doesn't show how long an elevation has been present, or whether it's temporary and linked to, for example, an infection, intense exertion or certain medications. This is why glucose is rarely assessed alone: an abnormal value is normally followed up with a repeat test on another occasion and compared with HbA1c to see whether the elevation is persistent.

It's also worth remembering that a normal fasting glucose doesn't rule out a sharp rise in blood sugar after meals, a pattern sometimes called impaired glucose tolerance, which can be an early sign of insulin resistance. Someone with risk factors for diabetes but a normal fasting glucose may therefore still benefit from discussing further investigation with a doctor, especially if HbA1c is at the same time in the upper range.

Frequently asked questions about Glucose (blood sugar)

Do I need to fast before a glucose test?

Yes, fasting glucose usually requires at least eight hours of fasting, during which only water is allowed. If the test is part of a health check with several markers, it's simplest to book a morning appointment and fast for the whole blood draw.

What is the difference between glucose and HbA1c?

Glucose shows blood sugar at the exact moment the sample was taken, while HbA1c reflects the average blood sugar over the last two to three months. Read more about HbA1c on its own page.

Is a single glucose value enough for a diagnosis?

No. A single fasting glucose result gives a snapshot and can be affected by temporary factors such as stress or illness. An abnormal value is therefore normally followed up with a repeat test and assessed together with HbA1c by a doctor.

Which health checks include glucose?

Fasting glucose is included in most of Labkollen's broad health checks, often together with HbA1c and blood lipids. All tests containing the marker are listed further down on this page.

Can I drink coffee before a fasting glucose test?

Black coffee without milk or sugar usually doesn't affect fasting glucose much, but recommendations vary between laboratories. The safest approach is to drink only water during the fast and wait to have coffee until after the blood draw.

Why can blood sugar be elevated even with a healthy diet?

Blood sugar is affected by more than diet, including sleep, stress, infections, certain medications and heredity. Even someone who eats healthily can have reduced insulin sensitivity, which is why glucose and HbA1c are often interpreted together in a health check.

How often should blood sugar be checked?

Without risk factors, a check every one or two years as part of a health check is usually enough. With overweight, family history, high blood pressure or previously abnormal values, more frequent checks are reasonable — discuss the interval with a doctor.

Health checks that include Glucose (blood sugar)

Glucose (blood sugar) is included in 10 of Labkollen's health checks. Analysis name in the result: Glukos.

  • Man +

    49 markers

    Labkollens mest omfattande kontroll för män – inklusive testosteron, PSA och hjärt-kärlmarkörer.

    2 095 krMed prenumeration (årlig hälsokontroll): 1 676 kr

    See the test

  • Kvinna +

    44 markers

    Labkollens mest omfattande kontroll för kvinnor – inklusive järnstatus, sköldkörtel och hormoner.

    2 095 krMed prenumeration (årlig hälsokontroll): 1 676 kr

    See the test

  • Standard

    37 markers

    Bred hälsokontroll över blodsocker, blodfetter, blodvärde, lever, njurar, sköldkörtel och vitaminer.

    1 795 krMed prenumeration (årlig hälsokontroll): 1 436 kr

    See the test

  • Seniorkollen

    32 markers

    Anpassad kontroll för dig över 65 med fokus på hjärta, njurar, sköldkörtel och näringsstatus.

    1 299 krMed prenumeration (årlig hälsokontroll): 1 039 kr

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  • Gravid

    26 markers

    Kontroll under graviditet – blodvärde, järn, sköldkörtel, vitaminer och hCG.

    1 099 krMed prenumeration (årlig hälsokontroll): 879 kr

    See the test

  • Hjärtkollen

    22 markers

    Blodfetter, ApoB och blodsocker för att bedöma risk för hjärt-kärlsjukdom.

    399 krMed prenumeration (årlig hälsokontroll): 319 kr

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  • Uthållighetssport

    16 markers

    För löpare, cyklister och simmare – järnstatus, energiomsättning och återhämtning.

    1 499 krMed prenumeration (årlig hälsokontroll): 1 199 kr

    See the test

  • Lagsport

    16 markers

    För lagidrottare – energi, järn, återhämtning och stresshormon.

    1 499 krMed prenumeration (årlig hälsokontroll): 1 199 kr

    See the test

  • Stresskollen

    5 markers

    Kortisol och basmarkörer vid långvarig stress, sömnbrist eller utmattningskänsla.

    499 krMed prenumeration (årlig hälsokontroll): 399 kr

    See the test

  • Sockerkollen

    3 markers

    Långtidsblodsocker, glukos och C-peptid vid misstanke om förhöjt blodsocker.

    449 krMed prenumeration (årlig hälsokontroll): 359 kr

    See the test

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Guides covering Glucose (blood sugar)

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