Metabolic blood test for obesity

Metabolic blood test for obesity with glucose, glycated haemoglobin, insulin, the HOMA-IR index, cholesterol, ApoB, ApoA-I, lipoprotein(a), high-sensitivity CRP, liver function with FIB-4, kidney function and a selection of vitamins and minerals. It assesses the metabolic, cardiovascular, liver and nutritional context beyond weight.

No prescription or appointment needed

Results in 3-5 working days

Includes: TSH · Glucose · Glycated haemoglobin · Insulin · HOMA-IR index · Lipid profile and ratios · Apolipoprotein B · Apolipoprotein A-I. 23 in total. See what each one measures

What it is for

It serves as a metabolic assessment of obesity and reviews four areas that can accompany it. First, glucose regulation and insulin resistance. Second, cardiovascular risk with cholesterol, ApoB and Lp(a). Third, the liver, through enzymes and FIB-4. And fourth, the kidney and nutritional context.

It can be used as a reference before a treatment or an intensive change in habits, although it is not a requirement that applies equally to everyone. The result is interpreted together with blood pressure, smoking, previous history, body composition and clinical records.

When it is recommended

Long-standing obesity without a recent metabolic assessment
A family history of type 2 diabetes, early heart attack or stroke
Fatty liver, borderline glucose or abnormal cholesterol in previous tests
Before starting a treatment, when you want a broad reference point
A discordance between LDL cholesterol and expected cardiovascular risk

Clinical comment

The difference from the profile for starting GLP-1 lies in the cardiovascular depth. ApoB helps identify a high number of atherogenic particles even when LDL does not look particularly high. Lp(a) depends mainly on genetics, and the guidelines recommend knowing it at least once in adulthood.

High-sensitivity CRP has a more limited role. It can add context in selected cases, but it rises with infections and other kinds of inflammation. A high result during an acute illness does not allow baseline risk to be assessed.

HOMA-IR estimates insulin resistance, but it has no universal cut-off point and is not a diagnosis of diabetes. FIB-4 is also a selection tool, not a direct measure of fibrosis. Both calculations are used to decide whether a closer look is required, not to reach a conclusion in isolation.

The vitamin and mineral block is included on clinical judgement. There is no recommendation requiring routine measurement in everyone with obesity, and a mild abnormality does not prove that it explains the symptoms. We have kept this breadth because the profile is aimed at people looking for a complete metabolic assessment and a reference point before intervening.

Dr. Antonio Mas

What is tested

TSH: The initial test for identifying a thyroid abnormality that could influence weight or cause similar symptoms.
Glucose: Measures fasting blood sugar.
Glycated haemoglobin (HbA1c): Reflects average glucose over the last two or three months.
Insulin: Measures fasting insulin and is interpreted together with glucose.
HOMA-IR index (calculated): Estimates the probability of advanced liver fibrosis from age, transaminases and platelets.
Lipid profile (total cholesterol, HDL, LDL, triglycerides) and ratios
Apolipoprotein B (ApoB): Estimates the number of atherogenic particles.
Apolipoprotein A-I (ApoA-I): The main protein in HDL particles, used to calculate the ApoB/ApoA-I ratio.
Lipoprotein(a) or Lp(a): A cardiovascular risk factor determined mainly by genetics.
High-sensitivity CRP: Measures low-grade inflammation, although it does not identify where it comes from.
Creatinine and eGFR: Assess kidney function.
Sodium and potassium: Measure the main electrolytes in the blood.
AST, ALT and GGT: Enzymes that give an indication of the state of the liver.
Total bilirubin and alkaline phosphatase: Complete the liver and biliary profile.
Full blood count: Checks the blood cells and provides the platelets for FIB-4.
FIB-4 index (calculated): Estimates the probability of advanced liver fibrosis from age, transaminases and platelets.
Ferritin: Estimates iron stores, although it can rise with inflammation or fatty liver.
Vitamin D (25-OH): Assesses vitamin D stores.
Vitamin B12: Measures the circulating concentration of cobalamin.
Folic acid (folate)
Uric acid: Completes the metabolic and kidney assessment.
Calcium: Gives basic information about mineral metabolism.
Magnesium: Measures serum magnesium.

These tests are used to calculate Índice HOMA-IR and Índice FIB-4. They are not separate tests.

How to prepare

Fast for 8 to 12 hours. You can drink water. If you have recently had a fever, an infection or inflammation, wait until you have recovered before measuring high-sensitivity CRP. If you take biotin supplements, stop them 48 hours before, because they can interfere with TSH and other tests.

You can add

Without another needle. It is offered when you order, so you do not have to decide now.

Male androgen profileAssesses androgen function better than total testosterone alone by including SHBG and calculating free testosterone.+€49.00
Female androgen profileBrings together the androgens and ovarian hormones used to investigate problems such as irregular cycles, acne or excess hair.+€59.00
Cholesterol particle size (Liposcale®)Analyses the size and number of the particles that carry cholesterol, information a standard blood test does not provide and that allows a better assessment of cardiovascular risk.+€123.00

Related blood tests

We have other profiles in Obesity with more or fewer tests:

The most comprehensive is not always the most useful. If you are not sure, the one we recommend to start with is Blood test before starting GLP-1.

What it is based on

European Association for the Study of the Liver, EASD y EASO · Diabetologia 67(11):2375-2392
EASL-EASD-EASO Clinical Practice Guidelines on the management of metabolic dysfunction-associated steatotic liver disease (MASLD)
Recommends looking for fatty liver with fibrosis in people with abdominal obesity and another metabolic factor, starting with a blood index such as FIB-4. That is the index this profile calculates from the full blood count and transaminases it already includes.
Mach F, Baigent C, Catapano AL, et al. · European Heart Journal 41(1):111-188
2019 ESC/EAS Guidelines for the management of dyslipidaemias: lipid modification to reduce cardiovascular risk
Recommends measuring ApoB to assess risk in people with obesity, diabetes or high triglycerides, because in them LDL cholesterol underestimates the number of particles that carry it.
Kronenberg F, Mora S, Stroes ESG, et al. · European Heart Journal 43(39):3925-3946
Lipoprotein(a) in atherosclerotic cardiovascular disease and aortic stenosis: a European Atherosclerosis Society consensus statement
Recommends measuring Lp(a) at least once in adult life: more than 90% of its concentration is determined by genetics and it hardly changes afterwards.

Protocol designed by Dr. Antonio Mas, specialist in Endocrinology and Nutrition, Spanish medical licence no. 080846289, and reviewed in September 2026.

This blood test is a standardised protocol and does not replace a medical consultation. If you have symptoms, a known condition or a complex clinical situation, speak to your doctor.