Top 6 Biomarkers for Diabetes Risk
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Diabetes affects millions in the UK, with numbers expected to rise significantly by 2025. Identifying early warning signs is crucial to prevent or delay the disease. Biomarkers - measurable indicators in the body - help assess diabetes risk effectively, often years before symptoms appear.
Here’s a quick overview of the top 6 biomarkers for diabetes risk:
- HbA1c: Reflects average blood sugar over 2-3 months. Levels above 48 mmol/mol suggest diabetes, while 39–46 mmol/mol indicates prediabetes.
- Fasting Plasma Glucose (FPG): Measures blood sugar after fasting. Levels ≥7.0 mmol/L indicate diabetes.
- Insulin Levels: High fasting insulin can signal insulin resistance, a precursor to type 2 diabetes.
- C-Reactive Protein (CRP): Indicates inflammation, which contributes to insulin resistance and diabetes development.
- Ferritin: High levels, even within normal ranges, are associated with increased diabetes risk due to inflammation.
- Triglyceride-to-HDL Ratio: A high ratio suggests insulin resistance and metabolic issues.
Why these matter: Combining these biomarkers improves accuracy in predicting diabetes risk, enabling earlier interventions. Regular testing, such as HbA1c and FPG, is widely available and recommended annually for those at risk.
Private providers like Epsom Blood Tests offer convenient testing services, including next-day results reviewed by doctors. Early detection through these biomarkers can lead to timely lifestyle changes or treatments, reducing long-term complications.
1. Glycated Haemoglobin (HbA1c)
What it measures
HbA1c provides insight into the percentage of haemoglobin in your blood that has glucose attached to it. This measurement reflects your average blood sugar levels over the past two to three months. It develops through an irreversible process known as glycation.
Unlike a regular glucose test, which captures blood sugar at a single moment, HbA1c offers a broader picture of blood sugar trends over time. Importantly, it’s not influenced by recent meals, making it a reliable indicator of long-term blood sugar control.
Association with diabetes risk
An HbA1c level of 48 mmol/mol (6.5%) or above indicates diabetes, while levels between 39–46 mmol/mol (5.7–6.4%) suggest prediabetes. These thresholds guide healthcare professionals in identifying individuals who may need immediate care or closer observation.
For working adults, HbA1c remains a key marker for assessing diabetes risk. Studies also show its independent association with type 1 diabetes, even when factors like age and sex are accounted for.
Clinical usefulness
The ability of HbA1c to provide a long-term view of blood sugar levels - without being affected by daily fluctuations or fasting - makes it a preferred tool for both screening and ongoing treatment monitoring.
In clinical settings, it serves two main purposes: diagnosing diabetes and monitoring how well treatment is managing the condition. UK guidelines recommend annual HbA1c testing for those at risk and twice-yearly testing for individuals already diagnosed with diabetes.
Private services, such as Epsom Blood Tests, offer HbA1c testing with next-day results and expert analysis. These services can streamline diagnosis and treatment planning, eliminating the need for a GP referral.
Interpretation considerations
Certain conditions, such as anaemia, haemoglobinopathies, or recent blood loss, can affect HbA1c results, as they alter red blood cell turnover. Healthcare providers take these factors into account when interpreting results to ensure accuracy.
Both NICE and Diabetes UK endorse HbA1c as a primary tool for diagnosing and monitoring diabetes. They recommend confirming borderline or unexpected results with repeat testing to ensure reliability.
In the UK, HbA1c is reported in mmol/mol, though percentages (%) are also used. This dual-format reporting underscores the importance of understanding how the test works, solidifying its role as a cornerstone in assessing diabetes risk and management.
2. Fasting Plasma Glucose
What it measures
Fasting plasma glucose (FPG) tests the level of glucose in your blood after an 8-hour fast, offering a snapshot of your glucose levels without the influence of recent meals. This makes it a valuable tool for identifying potential issues with insulin secretion or resistance. While HbA1c provides a picture of long-term glucose control, FPG focuses on your immediate metabolic state.
Association with diabetes risk
FPG results are divided into ranges that help gauge the risk of diabetes. Here's how they break down:
- Normal glucose tolerance: Below 5.6 mmol/L
- Impaired fasting glucose: Between 5.6 and 6.9 mmol/L
- Diabetes: 7.0 mmol/L or higher
Having impaired fasting glucose raises the risk of developing diabetes by about 1.4 times compared to normal levels.
Clinical usefulness
FPG is a key diagnostic tool, particularly for spotting individuals at risk before diabetes fully develops. Catching elevated glucose levels early allows for timely interventions, such as lifestyle changes or medications, which can help delay or even prevent diabetes.
Its affordability and simplicity mean it’s widely accessible across the UK. For example, Epsom Blood Tests offers FPG testing with next-day, doctor-reviewed results, all without needing a GP referral.
In clinical settings, FPG is used for both initial screenings and ongoing monitoring. Healthcare professionals track changes in glucose levels over time to evaluate whether someone is moving closer to insulin dependence.
Here’s a quick summary of FPG levels and their associated risks:
| FPG Level (mmol/L) | Interpretation | Risk Status |
|---|---|---|
| <5.6 | Normal | Low risk |
| 5.6–6.9 | Impaired fasting glucose | Approximately 1.4× increased risk |
| ≥7.0 | Diabetes | Requires immediate management |
Interpretation considerations
Several factors can impact FPG results, so preparation and context are crucial. To ensure accurate results, you need to fast for 8–14 hours - no food or caloric drinks allowed. Stress, illness, certain medications, and even poor sleep can temporarily raise glucose levels, so an unexpectedly high result should be confirmed with a repeat test or additional assessments like HbA1c.
FPG results should always be considered alongside other factors such as age, body mass index, family history, and additional clinical markers. Ethnicity and sex can also influence baseline FPG levels and their relevance for diabetes risk.
High FPG paired with normal insulin levels often points to insulin resistance, while high FPG with low insulin suggests beta cell dysfunction. This distinction can help healthcare providers pinpoint the root cause of an individual’s diabetes risk. By combining FPG insights with other data, clinicians can build a more detailed picture of a person’s overall risk profile.
3. Insulin Levels
What it Measures
Fasting insulin, like HbA1c and fasting plasma glucose, plays a key role in assessing metabolic health. This test measures the insulin hormone, produced by the pancreas, which helps regulate blood sugar levels. By evaluating fasting insulin, you get a snapshot of your baseline insulin production - an indicator that can reveal potential insulin resistance.
When insulin resistance occurs, the body compensates by producing more insulin. This baseline measure is essential for understanding your risk of developing diabetes.
Association with Diabetes Risk
Elevated fasting insulin levels are closely tied to a higher risk of type 2 diabetes. Research shows that abnormal insulin responses can significantly increase the likelihood of developing the condition, making fasting insulin a critical marker to watch.
Clinical Usefulness
Tracking insulin levels can help identify individuals at risk of diabetes, often before blood sugar levels show any abnormalities. This early detection is crucial because changes in insulin secretion often precede the onset of hyperglycaemia. When combined with other markers like glucose and HbA1c, fasting insulin enhances the precision of diabetes risk assessments.
Epsom Blood Tests includes fasting insulin in its comprehensive evaluations, providing timely results and expert guidance to support early interventions. Regular monitoring of fasting insulin can pave the way for lifestyle changes that may prevent diabetes from developing.
Interpretation Considerations
Normal fasting insulin levels usually fall between 2–20 mIU/L, though the exact range can vary depending on the laboratory. Readings above this range - especially when paired with normal or elevated fasting glucose - could point to insulin resistance and a heightened risk of diabetes. Always refer to the specific reference ranges provided by the testing lab.
Keep in mind that factors such as stress, illness, or certain medications can influence insulin levels. If results seem unusual, confirm them with repeat testing and interpret them alongside other biomarkers to get a complete picture of metabolic health.
4. C-Reactive Protein (CRP)
What it measures
C-Reactive Protein (CRP) is a protein produced by the liver in response to inflammation anywhere in the body. When tissues experience inflammation - whether due to infection, injury, or chronic conditions - the liver releases CRP into the bloodstream. CRP levels, measured in mg/L, serve as a reliable marker of systemic inflammation. Unlike biomarkers that directly assess glucose or insulin activity, CRP offers insight into the inflammatory processes that can contribute to metabolic disorders and insulin resistance. This makes it a valuable complement to glucose and insulin measurements.
Association with diabetes risk
CRP doesn’t just highlight inflammation - it also provides a deeper understanding of how inflammation ties into diabetes risk. Elevated CRP levels are closely associated with a higher likelihood of developing type 2 diabetes. Chronic low-grade inflammation disrupts insulin signalling and fosters insulin resistance, forming a key link between high CRP levels and diabetes risk. Studies consistently show that individuals with raised CRP levels face a considerably greater chance of developing type 2 diabetes.
Interestingly, CRP's significance extends to type 1 diabetes as well. Research has shown that higher CRP levels can predict the risk of type 1 diabetes up to 15 years before diagnosis. This underscores the role of inflammation in the development of various forms of diabetes, making CRP a useful early warning marker.
Clinical usefulness
CRP testing plays a significant role in improving diabetes risk prediction, particularly when combined with other biomarkers. Including CRP in a multi-biomarker panel enhances the ability to identify individuals at higher risk, enabling earlier interventions and more tailored prevention strategies.
At Epsom Blood Tests, CRP testing is included in comprehensive health checks. Blood samples are collected by experienced phlebotomists, and results are reviewed by doctors, ensuring timely and expert analysis.
Interpretation considerations
While CRP is a valuable inflammation marker, it’s important to note that it is not specific to diabetes. Elevated CRP levels can result from infections, chronic inflammatory conditions, or other unrelated factors, so recent illnesses or medications should be taken into account when interpreting results.
There is no universally accepted CRP threshold for predicting diabetes risk. However, levels above 3 mg/L are generally considered high and are linked to increased cardiovascular and metabolic risks. Rather than relying on a single cut-off, healthcare professionals should evaluate CRP results alongside other clinical findings and biomarkers for a more accurate assessment.
Ultimately, CRP reflects inflammation, which is widely recognised as a key factor in the development of type 2 diabetes. When combined with other biomarkers, it offers a more detailed and personalised risk profile, aiding in early intervention and prevention strategies.
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5. Ferritin
What it measures
Ferritin is a key biomarker that provides insight into both iron storage and inflammation levels in the body. It’s measured in micrograms per litre (µg/L) in the UK. Normal ranges differ slightly by gender, with men typically falling between 30–300 µg/L and women between 15–200 µg/L, though these can vary depending on the laboratory.
Ferritin plays a dual role in the body. On one hand, it reflects the amount of stored iron. On the other, it acts as an acute-phase reactant, meaning its levels rise during inflammation. This dual functionality makes it a useful marker for assessing both iron metabolism and the inflammatory processes that can contribute to metabolic conditions.
Association with diabetes risk
Numerous studies have linked higher ferritin levels - even those within the normal range - to an increased risk of developing type 2 diabetes. This connection likely stems from ferritin's dual role in iron storage and as an indicator of chronic inflammation.
One standout piece of research is the MONICA/KORA case-cohort study, which followed participants over 14 years. The study found that higher ferritin levels were significantly associated with the onset of type 2 diabetes, even after accounting for factors like age, sex, BMI, and survey data. Participants with elevated baseline ferritin levels had a greater hazard ratio for developing diabetes compared to those with lower levels.
Ferritin’s predictive power is even stronger when combined with other markers, such as HbA1c and fasting glucose. People in the highest ferritin quartile showed a notably higher risk of developing diabetes compared to those in the lowest quartile. This makes ferritin a valuable tool for identifying individuals at risk before symptoms appear.
Clinical usefulness
Incorporating ferritin into diabetes risk assessments can help identify individuals who may benefit from early intervention. When combined with other biomarkers like fasting glucose, insulin, and C-reactive protein (CRP), ferritin provides added predictive value.
Risk models that include ferritin alongside other markers achieve greater accuracy, with an area under the ROC curve reaching up to 0.78. This highlights ferritin’s role in improving patient stratification and guiding preventive strategies. It underscores the importance of using multiple biomarkers for a well-rounded health assessment.
At Epsom Blood Tests, ferritin testing is offered as part of comprehensive health checks. Blood samples are collected by skilled phlebotomists, with results available the next day. Reports include expert analysis, helping patients understand their risk profile and take steps towards prevention or management.
Interpretation considerations
Ferritin levels can be influenced by factors beyond iron storage, including inflammation, liver disease, infections, and metabolic syndrome. This means that an elevated ferritin level doesn’t automatically indicate iron overload; it could also signal underlying inflammatory conditions that increase diabetes risk.
If ferritin levels exceed the upper limit, further evaluation is needed to determine whether the cause is iron overload, chronic inflammation, or metabolic syndrome. This may involve additional tests, such as liver function assessments and inflammatory markers. Persistent elevation should prompt a deeper investigation into possible underlying conditions.
For individuals with elevated ferritin, healthcare providers often examine other risk factors like obesity, family history, and signs of metabolic syndrome. Lifestyle changes - such as weight management, dietary adjustments, and regular exercise - are frequently recommended to lower ferritin levels and reduce diabetes risk. In some cases, referral to a specialist may be necessary to address iron overload or related inflammatory issues.
Ferritin results should always be interpreted within the broader clinical context. Experts note that ferritin is not only a marker of iron metabolism but also a surrogate for chronic low-grade inflammation, both of which are linked to the development of type 2 diabetes. This makes it an invaluable component of multi-marker panels for assessing diabetes risk.
The Key Biomarkers to Measure With a Blood Test | Dr. Casey Means & Dr. Andrew Huberman
6. Triglyceride-to-HDL Ratio
In addition to glucose and insulin markers, lipid ratios offer valuable insights into metabolic health and the risk of developing diabetes.
What it measures
The triglyceride-to-HDL ratio examines the relationship between two important blood lipids: triglycerides (a type of fat) and high-density lipoprotein (HDL) cholesterol. To calculate it, you divide the triglyceride level by the HDL cholesterol level, both measured in millimoles per litre (mmol/L), which is the standard in the UK. For instance, if someone has triglycerides of 2.0 mmol/L and an HDL level of 1.0 mmol/L, the resulting ratio would be 2.0. This measurement provides a snapshot of metabolic health.
Understanding this ratio is key to evaluating its role in assessing diabetes risk.
Association with diabetes risk
A higher triglyceride-to-HDL ratio has been strongly linked to an increased risk of type 2 diabetes. Studies indicate that individuals with a ratio in the highest quartile face a 2- to 3-fold greater chance of developing type 2 diabetes compared to those in the lowest quartile. This ratio is particularly useful for identifying people who might have normal fasting glucose or HbA1c levels but are still experiencing hidden insulin resistance.
Clinical usefulness
This ratio is a practical and cost-effective marker, as it can be easily calculated from a standard lipid panel. A ratio above 1.7 mmol/L is generally considered elevated, with some experts suggesting that levels above 2.0 mmol/L may signal an even greater concern, especially when combined with other risk factors. For example, consider a 52-year-old man with a BMI of 29 kg/m², triglycerides of 2.4 mmol/L, and HDL of 0.9 mmol/L. His ratio would be 2.67, highlighting a high risk for diabetes. At Epsom Blood Tests, comprehensive lipid panels - including triglyceride and HDL measurements - are available as part of routine health checks. Samples are collected by skilled phlebotomists, and results are reviewed by experts the next day, ensuring a thorough evaluation of metabolic health.
Interpretation considerations
Proper interpretation of the triglyceride-to-HDL ratio is essential. Several factors can influence the results, such as recent food intake, alcohol consumption, medications, and underlying conditions like hypothyroidism or nephrotic syndrome. To ensure accuracy, fasting samples are preferred. However, this ratio should not be viewed in isolation. Instead, it should be part of a broader metabolic assessment. An elevated ratio may point to metabolic syndrome and should prompt lifestyle changes, such as adopting a Mediterranean-style diet, increasing physical activity, and managing weight, to lower the risk of diabetes and cardiovascular disease.
Additionally, individual factors play a role. For example, South Asians are at a higher risk of diabetes even at lower BMI and lipid thresholds, emphasising the importance of personalised interpretation. Regular monitoring of this ratio can help track metabolic health improvements and guide preventative measures.
Biomarker Comparison Table
To complement the detailed analyses above, here’s a quick-reference table summarising the key performance metrics of each biomarker. This snapshot highlights their predictive power, clinical importance, and ease of testing, making it easier to compare their roles in diabetes management.
| Biomarker | Predictive Power | Clinical Relevance | Ease of Testing | Key UK Reference Range |
|---|---|---|---|---|
| HbA1c | High | High | Very Easy | Normal: <42 mmol/mol Pre‐diabetes: 42–47 mmol/mol Diabetes: ≥48 mmol/mol |
| Fasting Plasma Glucose | Moderate–High | High | Very Easy | Normal: <5.6 mmol/L Impaired: 5.6–6.9 mmol/L Diabetes: ≥7.0 mmol/L |
| Insulin Levels | Moderate | Moderate | Moderate | Fasting: <25 mIU/L (typical) |
| C-Reactive Protein (CRP) | Moderate | Low–Moderate | Easy | Low risk: <3 mg/L |
| Ferritin | Moderate | Moderate | Easy | Men: 30–400 µg/L Women: 13–150 µg/L |
| Triglyceride-to-HDL Ratio | Moderate–High | High | Very Easy | Low risk: <2 High risk: >4 |
Key Insights
HbA1c is often regarded as the gold standard for assessing diabetes risk. It reflects the average blood glucose levels over three months and is not significantly affected by short-term changes, making it highly reliable. This test is widely used in both NHS and private clinics.
Fasting plasma glucose offers strong clinical relevance but can be influenced by temporary factors like stress or illness. Both HbA1c and fasting plasma glucose tests are available at Epsom Blood Tests, where results are reviewed by doctors and returned the next day.
The triglyceride-to-HDL ratio provides valuable insights into metabolic health. A ratio greater than 2.0 mmol/L signals an elevated risk, with higher values often linked to insulin resistance and other metabolic issues.
Combining Biomarkers for Better Accuracy
Studies suggest that relying on multiple biomarkers significantly improves predictive accuracy. For example, using a single marker gives an accuracy of 0.75, but combining several can increase it to 0.78 or more. At Epsom Blood Tests, comprehensive panels are available to provide a full metabolic profile, offering a deeper understanding of health risks compared to standalone tests.
A Practical Testing Strategy
A tiered approach often works best. Start with HbA1c and fasting glucose testing for a baseline assessment. For borderline results, additional markers like insulin levels, CRP, ferritin, and lipid profiles can offer more clarity. This method balances affordability with thorough risk evaluation, ensuring a well-rounded perspective on metabolic health.
Conclusion
Keeping track of key biomarkers - HbA1c, fasting plasma glucose, insulin, CRP, ferritin, and the triglyceride-to-HDL ratio - offers a reliable way to detect diabetes risk early, with predictive accuracy ranging between 0.76 and 0.78. This approach significantly outperforms relying on individual markers alone. Studies show that changes in some of these biomarkers can be identified as early as 15 years before a clinical diabetes diagnosis, giving a crucial opportunity to take preventive action.
For individuals at risk, regular monitoring is essential. Experts recommend annual HbA1c and fasting glucose tests. This proactive approach allows for timely lifestyle changes or medical interventions as biomarker trends shift, helping to manage risk more effectively.
Epsom Blood Tests makes regular monitoring straightforward and accessible. Their in-clinic testing offers next-day results reviewed by professionals, earning high satisfaction from patients. With comprehensive diabetes risk panels priced between £40 and £120, this service combines affordability with convenience. Features like direct online booking and clear pricing remove common barriers, making private testing a practical choice for many.
FAQs
Why is using multiple biomarkers more effective for predicting diabetes risk than relying on a single one?
Combining several biomarkers like HbA1c, fasting glucose, and insulin levels gives a broader understanding of your risk for diabetes. These markers each provide distinct information about how your body manages blood sugar, and when assessed together, they can reveal patterns or early signs that might not be obvious from a single measurement.
Take HbA1c, for instance - it shows your average blood sugar levels over a longer period. Fasting glucose, on the other hand, gives a snapshot of your current blood sugar levels. Insulin levels help determine how well your body processes sugar. When these are analysed collectively, healthcare professionals can offer more precise predictions and create prevention or treatment plans that are tailored specifically to you.
What lifestyle changes can help reduce diabetes risk if biomarkers indicate a higher likelihood of developing the condition?
If your biomarkers indicate a higher likelihood of developing diabetes, making some lifestyle adjustments can help improve your overall health. Start with a balanced diet that includes plenty of whole grains, vegetables, and lean proteins, while cutting back on processed foods and added sugars. Incorporating regular physical activity, such as brisk walking or cycling, can also boost insulin sensitivity and help maintain healthy blood sugar levels.
Other important factors include managing stress effectively, keeping a healthy weight, and ensuring you get enough restorative sleep. Regular health checks, like those available at Epsom Blood Tests, can be a useful way to track your progress and keep an eye on essential health markers over time.
What factors could influence the accuracy of biomarker tests for assessing diabetes risk?
Several things can influence how reliable biomarker tests are when assessing diabetes risk. Factors like recent illnesses, medications, stress, and even lifestyle choices - such as what you eat and how active you are - can all play a role. For instance, fasting glucose levels might rise temporarily due to stress or certain medications, which could skew the results.
Following pre-test instructions is crucial, especially if fasting is required. Skipping this step could lead to inaccurate results. If you're uncertain about how to prepare or have questions about your results, it's always a good idea to reach out to a healthcare professional for advice. They can provide clarity and ensure you're on the right track.