Diagnostic Tests for Metabolic Health and Diabetes Evaluation

Chapter 10 · Vihang Rahul Vasa

The following medical diagnostic tests are commonly used to evaluate and monitor metabolic health and diabetes. Initially, these tests may be done once every six months; as your condition stabilises and improves, your doctor may reduce the frequency to once a year. It is important to understand that not all tests are necessary for every person, and not all need to be done at once. It is your treating doctor who will decide which tests are needed for you and how often they should be repeated, based on your individual condition and where clinically indicated.

1. Blood Pressure (At Every Visit)

• High blood pressure and diabetes are a dangerous partnership, together they multiply the strain on your heart, kidneys, eyes, and brain.

• Have your blood pressure checked regularly by your doctor: ideally at every visit, and at the frequency your doctor advises.

2. Body Weight (Ongoing)

• Keep an eye on your weight regularly: it is the simplest health tracker you own.

• Any rapid change, whether gain or loss, should be reported to your doctor immediately: unexplained rapid change, whether loss or gain, can signal uncontrolled plasma glucose (blood sugar) or another problem and needs prompt attention.

3. Eye Examination (Yearly)

• Comprehensive eye checkup with retinal evaluation: Examines the blood vessels at the back of your eye to detect retinopathy due to diabetes early. Since diabetes affects micro vessels first, the retina is often where the earliest signs of damage appear. This is commonly done once a year, though the right frequency for you depends on your diabetes type, duration, previous retinal findings, and your doctor’s clinical guidance.

4. Foot Examination (Yearly: by your doctor)

• A yearly foot examination by your doctor is essential, because diabetes can silently damage the nerves of the feet, sensory neuropathy, long before you feel anything is wrong.

• The doctor first inspects the skin for changes, dryness, cracks, colour changes, and looks for callosities (patches of hardened skin) and any ulceration (open sores), however small. The doctor will also examine the arches of your feet, and any changes in them over time.

• Sensation is then tested: the sense of coarse touch (often checked with a fine nylon filament pressed gently on the sole) and the sense of vibration (checked with a tuning fork placed on the toe): loss of these senses is one of the earliest signs of nerve damage.

• Do not wait for the yearly check if you notice numbness, tingling, or burning in your feet: report it to your doctor right away. Daily foot care has its own chapter (see Chapter 38).

5. Ear Examination (Yearly: if indicated)

• Clinical ear checkup and audiometry test: Recommended annually, especially if you notice any change in your hearing. (See Chapter 61 for how diabetes affects the ears.)

6. Bone Density (When Your Doctor Advises)

• DEXA scan, Dual-Energy X-ray Absorptiometry, the bone-density scan, A quick, low-radiation scan that checks how strong your bones are. In Type 2 Diabetes, this scan plays an important role: in a person living with diabetes, bones can break more easily, and a broken bone takes much longer to heal. So it helps to know the state of your bones, especially after fifty, after the menopause, after any fracture, or if you have taken steroids for a long time. Your doctor decides if and when it is due (see Chapter 40).

7. Urine Tests

• Urine Routine (Complete Urine Examination): A simple, inexpensive first-line test that checks for sugar, protein, ketones, and signs of infection in the urine.

• Microalbumin (Urine), Detects tiny amounts of albumin leaking into the urine, the earliest warning sign of diabetes-related kidney damage, often years before other tests show it.

These simple urine tests are inexpensive, widely available, and among the earliest indicators of how diabetes is affecting the body. Microalbumin in urine is an early sign of nephropathy (diabetes-related kidney damage): if it is detected, it is advisable to consult a nephrologist (kidney specialist).

8. Blood Glucose and Diabetes Markers

• Fasting Plasma Glucose (FPG): Measures plasma glucose (blood sugar) after an overnight fast of 8–12 hours.

• Postprandial Plasma Glucose (PPPG): Measures plasma glucose (blood sugar) 2 hours after a meal, to assess how your body handles glucose after eating.

• HbA1c (glycated haemoglobin): Reflects your average plasma glucose (blood sugar) over the past 3 months. This is a primary and reliable test used to assess long-term glycaemic control.

These tests are used to diagnose and monitor Type 2 Diabetes.

9. Insulin and Metabolic Function

• Serum Insulin (Fasting): Measures the level of insulin in your blood after fasting. Helps assess the degree of insulin resistance, which is the root cause of most metabolic dysfunction. Requires an overnight fast.

10. Lipid Profile

• Total Cholesterol, LDL (Low-Density Lipoprotein), HDL (High-Density Lipoprotein), and Triglycerides (Fasting): A comprehensive blood test that evaluates your fat metabolism. Elevated triglycerides and LDL, or low HDL, are key indicators of metabolic imbalance and cardiovascular risk. Detects hypertriglyceridaemia. Requires an overnight fast.

11. Kidney Function

• Renal Function Test (RFT): Evaluates how well your kidneys are filtering waste. Includes serum creatinine, blood urea, and urine albumin. Essential for people living with diabetes, as diabetes is a leading cause of kidney damage.

12. Thyroid Function

• T3, T4, and TSH: Screens for thyroid disorders such as hypothyroidism and hyperthyroidism, which can significantly impact metabolism, weight, energy levels, and plasma glucose (blood sugar) control. Thyroid dysfunction often coexists with diabetes and can complicate management if undetected (see Chapter 35).

13. Inflammation Markers

• C-Reactive Protein (CRP): Measures non-specific inflammation in the body. CRP rises within hours of new inflammation and falls quickly when it settles, so it reflects current inflammation. Chronic low-grade inflammation is common in diabetes and metabolic syndrome, and raised levels may point to higher heart risk or an underlying infection.

• Erythrocyte Sedimentation Rate (ESR): Also a non-specific marker of inflammation. ESR rises and falls slowly, over days to weeks, so it better reflects older, chronic, or long-lasting inflammation. It is usually read together with CRP.

14. General Health

• Complete Blood Count (CBC): A broad screening test that evaluates your red blood cells, white blood cells, and platelets. Helps detect anaemia, infections, and other conditions that can affect your overall health and diabetes management.

15. Pancreatic Enzymes

• Serum Amylase and Serum Lipase: Measure the enzymes produced by your pancreas. Useful in assessing pancreatic health, especially if there is suspicion of pancreatitis or other pancreatic dysfunction, which can directly affect insulin production.

16. Vitamins

• Vitamin B12 and Vitamin D: Both can run low in people with diabetes, and low levels are easy to miss. Low B12 can cause tiredness and nerve symptoms (some diabetes medicines can lower B12 over time); low Vitamin D affects bones, muscles, and insulin sensitivity. A simple blood test, usually once a year, rules both out.

17. Tuberculosis Screening

• Interferon-Gamma Release Assay (IGRA): A blood test for tuberculosis infection. People with diabetes could carry a higher risk of TB, especially in India; your doctor may advise this test if there is any suspicion or exposure.

18. Hormonal and Stress

• Cortisol (8 AM, fasting): Measures your morning cortisol level. Cortisol directly influences plasma glucose (blood sugar) by triggering glucose release from the liver. Chronically elevated cortisol from stress can worsen insulin resistance and make diabetes harder to control.

19. Liver Health

• Liver Function Test (LFT): Assesses how well your liver is functioning through enzymes and protein levels.

• FIB-4 (Fibrosis-4) Score: A calculated score using age, liver enzymes, and platelet count to estimate the degree of liver fibrosis (scarring).

• Fibroscan (LSM + CAP): explained in full (see Chapter 8).

Key Insight

No single test gives the full picture. A combination of sugar, insulin, lipid, liver, kidney, and thyroid tests helps detect metabolic disease early: often before symptoms appear. Think of these tests as an annual health audit: they reveal what is happening inside your body long before your body shows it on the outside.

Routine annual testing like this can identify early metabolic dysfunction years before it progresses to diabetes or liver disease, allowing timely lifestyle correction and medical intervention. Discuss with your doctor which tests are right for you, and make them part of your annual health routine.

Illustration: Chapter 10 illustrated summary. The wider health picture includes blood and urine tests, eyes and feet, heart and blood pressure, liver, kidneys and thyroid, and other checks when indicated.

Chapter 10 The wider health picture includes blood and urine tests, eyes and feet, heart and blood pressure, liver, kidneys and thyroid, and other checks when indicated. No single test gives the full picture; the doctor decides which tests and how often.

Chapter at a glance: an AI-generated illustration to be read with the chapter, not instead of it. The people shown are not real.