What is the difference between the Commencement and Monitoring options?

Commencement is a wider baseline, adding iron studies, vitamin B12, folic acid, thyroid antibodies, cortisol and lipoprotein(a). Monitoring repeats the core checks and adds pancreatic enzymes, magnesium, hsCRP and a urine kidney check for use during treatment.

Do I need to fast for weight loss blood tests?

Fasting is not required. Coming in fasted, with water only, helps if you can manage it, because it makes the glucose, insulin and HOMA-IR results easier to interpret.

HOMA-IR is a score worked out from your glucose and insulin results that gives an estimate of insulin resistance. It is not part of routine UK testing, so it is read alongside your HbA1c, weight and waist size.

Heart & metabolic

Private blood test

Weight Loss Blood Tests

Blood tests for weight management: a baseline before starting treatment, and a monitoring panel during it.

47 biomarkers
Fasting recommended

Choose your panel

Before starting47 biomarkers£219Monitoring41 biomarkers£179

Weight Loss Commencement

£219Includes sample collection

Book this test Ask a question

We confirm your appointment and any preparation, such as fasting, before you attend.

What’s included

47 biomarkers in Weight Loss Commencement.

Fasting recommended before this test

Heart & cholesterol7

Cholesterol and other fats in the blood that are linked to heart health.

Apolipoprotein B
HDL
LDL
Lipoprotein (a)
Total Cholesterol
Total Cholesterol / HDL Cholesterol Ratio
Triglycerides

Blood sugar & diabetes5

How your body manages sugar, including your average level over recent months.

C-peptide
Glucose
Insulin
HbA1c
HOMA-IR

Liver6

Enzymes and proteins that show how well your liver is working.

Alanine Aminotransferase (ALT)
Albumin
Alkaline Phosphatase (ALP)
Aspartate Aminotransferase (AST)
Gamma-Glutamyltransferase (GGT)
Total Bilirubin

Kidneys3

How well your kidneys filter waste from your blood.

Creatinine
Estimated Glomerular Filtration Rate (eGFR)
Urea

Body salts & minerals5

Electrolytes and minerals that help your nerves, muscles and heart work properly.

Calcium (adjusted)
Chloride
Phosphate
Potassium
Sodium

Iron & anaemia4

Your iron levels and stores, a common cause of tiredness when low.

Ferritin
Iron
Total Iron Binding Capacity (TIBC)
Transferrin Saturation

Vitamins3

Key vitamins for energy, nerves, bones and healthy blood.

Folic acid
Vitamin B12
Vitamin D

Blood count1

Your red cells, white cells and platelets.

Full Blood Count

Thyroid5

How well your thyroid is working, and antibodies linked to thyroid conditions.

Anti-Thyroglobulin Antibody (Anti-Tg)
Anti-Thyroid Peroxidase Antibody (Anti-TPO)
Free Thyroxine (FT4)
Free Tri-iodothyronine (FT3)
Thyroid Stimulating Hormone (TSH)

Hormones & fertility8

Reproductive, stress and adrenal hormones.

Cortisol
Follicle Stimulating Hormone
Free Androgen Index
Luteinising Hormone
Oestradiol
Prolactin
Sex Hormone Binding Globulin (SHBG)
Testosterone

About this test

Is the Weight Loss Blood Tests right for you?

Who it’s for

You are about to start a medically supervised weight-management programme and want a baseline set of blood tests first.
Your prescriber or weight-management service has asked for blood tests before or during treatment.
You want to check for conditions linked to weight, such as type 2 diabetes, high cholesterol and fatty liver disease, or conditions that can cause weight gain, such as an underactive thyroid.
You are losing weight and want to check that your kidneys, liver and nutrient levels stay healthy along the way.

What it can show

Both options check blood sugar (HbA1c, glucose, insulin and the HOMA-IR insulin resistance score), cholesterol including apolipoprotein B, kidney and liver function, a full blood count, ferritin, vitamin D and thyroid function (TSH and free T4).
Both options include hormones: testosterone, SHBG, free androgen index, LH, FSH, oestradiol and prolactin. These can help show hormone conditions linked to weight, such as PMOS (previously PCOS) or low testosterone.
The Commencement option adds a fuller baseline: iron studies, vitamin B12, folic acid, free T3, thyroid antibodies, C-peptide, lipoprotein(a) and cortisol. Cortisol can help when a doctor is considering Cushing’s syndrome, a rare cause of weight gain.
The Monitoring option adds lipase and pancreatic amylase (enzymes that rise when the pancreas is inflamed), magnesium, hsCRP and a urine albumin to creatinine ratio, an early check on the kidneys.
Liver tests can show changes such as those seen in fatty liver disease (MASLD), which is more common in people living with overweight and often causes no symptoms.

What it can’t tell you

These tests check your general health before and during weight management. They do not decide whether a particular treatment is right for you; that is a decision for your prescriber.
Glucose, insulin and HOMA-IR are designed for a fasting sample, and insulin is not routinely used in UK practice to assess insulin resistance. A non-fasting result is harder to interpret.
Cortisol and testosterone change through the day and are highest in the morning. A single cortisol result is not usually enough to confirm or rule out Cushing’s syndrome.
If you develop sudden, severe tummy pain, especially pain that spreads to your back, call 999 (or 112) or go to an emergency department rather than waiting for a blood test.
Results need to be interpreted alongside your symptoms and treatment. Diagnosis, prescribing and changes to treatment are with your prescriber, GP or specialist.

Before your test

You do not need to fast for either option. If you can, come having had only water since the night before, as glucose, insulin and HOMA-IR are easiest to interpret on a fasting sample.
Book an early morning appointment if you can. Cortisol (Commencement option) is best measured around 8 to 9am, and testosterone before 11am.
Biotin (vitamin B7), found in some hair, skin and nail supplements, can affect some hormone and thyroid results. Tell us if you take it, and if you take a high dose (5mg or more a day), stop it for a week before your test if it is safe to do so.
The Monitoring option includes a urine albumin to creatinine ratio, so you will also be asked for a small urine sample. Tell us about any steroid medicines, as they affect cortisol and blood sugar.

Your results

Usually within a couple of working days. We email your results once a doctor has reviewed them.

How it works

From booking to results in three steps.

Step 1
Request your test
Send a booking request online or call us. We confirm your clinic, appointment time and any preparation.
Step 2
Visit the clinic
A short appointment for professional sample collection at Greysteel or Letterkenny. No GP referral needed.
Step 3
Receive your results
Usually within a couple of working days, emailed to you once a doctor has reviewed them.

Common questions

Questions about this test.

A baseline shows how your blood sugar, cholesterol, liver, kidneys, thyroid and hormones look before you start. Later results can be compared with it, and any condition found can be managed straight away rather than waiting until you have lost weight.