Ulta Lab Tests

Weight Management Tests

This hub is for adults with overweight/obesity, stubborn weight change, metabolic risk, PCOS features, or suspected NAFLD, those starting medication or pre/post-bariatric surgery, and clinicians coordinating workups.


Primary domains: Glycemia (A1c, fasting glucose, ± OGTT, ± fructosamine) · Insulin resistance (fasting insulin → HOMA-IR calculated) · Lipids/atherogenic particles (lipid panel, ApoB, Non-HDL-C, Lp(a)) · Inflammation(hs-CRP) · Liver (AST/ALT/ALP/GGT, bilirubin, platelets for FIB-4 context) · Kidney (creatinine/eGFR, uACR) · Thyroid (TSH ± FT4) · Nutrients (B12, vitamin D, iron studies as appropriate) · Uric acid (metabolic/gout risk).


Use these tests to establish baseline risk, assess therapy eligibility, triage comorbidities (diabetes, NAFLD, CKD, dyslipidemia, thyroid), and monitor progress—always with clinician guidance.

What It Tests

  • Screening/Early detection: Baseline cardiometabolic risk (A1c/glucose, lipids/ApoB, Lp(a), blood pressure context), thyroid screen, liver/kidney checks, nutrient gaps relevant to weight and energy.

  • Diagnosis/Triage: Clarify hyperglycemia/insulin resistance, secondary contributors (thyroid dysfunction, NAFLD, CKD), and inherited risk (Lp(a)).

  • Monitoring: Track change with lifestyle or clinician-guided therapy; prefer trends (same lab, similar conditions) over single values.

Key principle: Interpret patterns trends clinical context (meds, sleep, diet, illness) rather than isolated lab numbers.

Key Tests

Test Also called (synonyms) What it measures Typical prep Specimen TAT Related panels Use type Timing notes / caveats
A1c HbA1c Avg glycemia (~3 mo) No fast Blood 1–2 d Cardiometabolic, Prediabetes Screen/Mon Unreliable in anemia, Hb variants, pregnancy, CKD → consider FPG/OGTT/fructosamine.
Fasting Plasma Glucose FPG Point-in-time glucose 8–12 h fast Blood Same–1 d Prediabetes Screen/Dx/Mon Illness, meds, alcohol can shift values.
OGTT (75 g, 2 h) Glucose tolerance test Post-challenge glucose Prep per lab; time-intensive Blood Same day Prediabetes/PCOS Dx Useful when A1c discordant or for gestational risk.
Fructosamine — 2–3 week glycemia No fast Blood 1–2 d Prediabetes Mon Helpful when A1c unreliable or rapid changes.
Fasting Insulin — Insulin resistance context 8–12 h fast Blood 1–2 d Insulin Resistance Dx/Mon Combine with FPG to calculate HOMA-IR(derived, not a lab).
Lipid Panel TC/LDL-C/HDL-C/TG Atherogenic lipids Fast often preferred Blood 1–2 d Cardiometabolic Screen/Mon Non-fasting acceptable in some labs; TG most affected.
Apolipoprotein B ApoB Atherogenic particle number None (per lab) Blood 1–3 d Cardiometabolic Risk/Mon Refines risk beyond LDL-C; stable with fasting.
Non-HDL-C TC − HDL-C All atherogenic cholesterol Derived — — Cardiometabolic Risk/Mon Useful when TG high; no extra blood needed.
Lipoprotein(a) Lp(a) Genetic lipoprotein risk None Blood 1–7 d Cardiometabolic Risk (one-time) Genetically determined; typically once-in-lifetime.
hs-CRP High-sensitivity CRP Low-grade inflammation None; test when well Blood 1–2 d Cardiometabolic Risk/Mon Avoid during acute illness/flare.
ALT / AST / ALP / bilirubin, albumin LFTs Liver injury/function None; avoid heavy alcohol 24–48 h Blood 1–2 d NAFLD Screen Screen/Dx/Mon Rapid weight loss can transiently raise ALT; meds/alcohol confound.
Platelet count (CBC) — Needed for FIB-4 calc None Blood Same–1 d NAFLD Screen Risk/Mon FIB-4 (Age, AST, ALT, Platelets) triages fibrosis risk (not diagnostic).
Creatinine eGFR — Kidney filtration None; hydrate normally Blood Same–1 d Kidney Risk Screen/Mon Track trends; extremes of muscle mass alter estimates.
uACR Urine albumin/creatinine ratio Early kidney damage risk First-catch urine ideal Urine 1–2 d Kidney Risk Screen/Mon Abnormal even with normal eGFR; pair with eGFR.
TSH and Free T4 — Thyroid status None Blood 1–2 d Thyroid Screen/Dx/Mon Biotin can interfere in some assays; correlate with symptoms.
Vitamin B12 Cobalamin B12 status None Blood 1–3 d Bariatric/Metformin Screen/Mon Monitor on metformin or post-bariatric; MMA adds context.
Vitamin D (25-OH) 25-hydroxy D Vitamin D status None Blood 1–3 d Bone/Metabolic Screen/Mon Interpret with Ca/P; seasons matter.
Iron studies Ferritin, Iron, TIBC, TSAT Iron stores/transport AM ± fasting Blood 1–2 d Bariatric/Anemia Dx/Mon Ferritin ↑ with inflammation; check CRP; heavy menses/post-op.
Uric Acid — Gout/metabolic risk None Blood 1–2 d Metabolic Risk/Mon Weight loss/diuretics can shift levels.

When to Test

  • Before starting a structured weight program or anti-obesity medication.

  • Stubborn weight gain or central adiposity with fatigue → screen glycemia, lipids/ApoB, TSH, LFTs.

  • Metabolic syndrome features (↑ waist, TG, BP, glucose, low HDL-C).

  • PCOS signs (irregular cycles, hirsutism, acne) → add androgens, A1c/FPG/insulin (see Hormone hub).

  • Suspected NAFLD/MAFLD or elevated ALT → add platelets for FIB-4 context (clinician decides imaging).

  • Kidney risk (diabetes, hypertension) → pair eGFR uACR.

  • Bariatric pre-op baseline & post-op maintenance panels.

  • On therapy (GLP-1/GIP or others) → periodic A1c/glucose, lipids/ApoB, CMP/eGFR, ± B12/vitamin D/iron per regimen.

  • Family history of premature ASCVD or high Lp(a) → once-in-lifetime Lp(a).

How to Prepare

  • Fasting: 8–12 h for FPG, fasting insulin, and many lipid protocols (confirm requisition). A1c does not require fasting.

  • Medications & supplements: Disclose biotin, steroids, thyroid meds, statins, metformin, GLP-1/GIP, diuretics, androgens; do not stop meds without clinician guidance.

  • Alcohol/exercise: Avoid heavy alcohol 24–48 h and vigorous exercise right before draw (can affect TG, CK, LFTs).

  • Hydration: Maintain usual intake; avoid deliberate dehydration.

  • Consistency: For trending, use the same lab and similar conditions (time of day, fasting).

Interpreting Results

  • Glycemia: A1c ≈ 3-month average; confirm with FPG/OGTT if A1c is unreliable. Fructosamine helps with rapid change or A1c limitations.

  • Insulin resistance: Fasting insulin FPG → HOMA-IR (calculated). Indices inform risk, not diagnoses on their own.

  • Lipids/ApoB/Lp(a): ApoB = atherogenic particle number; Lp(a) is genetically determined and typically measured once; Non-HDL-C captures all atherogenic cholesterol.

  • Liver/NAFLD: Mild ALT/AST elevations are common; FIB-4 (derived from age, AST, ALT, platelets) triages fibrosis risk—not diagnostic. Imaging/management is clinician-directed.

  • Kidney: Use eGFR uACR together to refine risk better than either alone.

  • Thyroid: TSH is the primary screen; interpret with FT4 and symptoms; check biotin exposure.

  • Bariatric/nutrients: Monitor B12, iron, vitamin D, Ca/P, PTH per program.

  • No self-titration of medications or supplements based solely on labs—coordinate with your clinician.

Related Conditions

  • Diabetes & Prediabetes (A1c/FPG/OGTT)

  • Heart & Cardiovascular Risk (lipids, ApoB, Lp(a), hs-CRP)

  • Liver Health / NAFLD (LFTs, FIB-4 context)

  • Kidney Health (eGFR uACR)

  • Thyroid & Hormone (TSH; PCOS/androgens; Low T in men)

  • Nutrition & Micronutrients (B12, vitamin D, iron)

  • Sleep Apnea (screening context)

Bundles & Panels

FAQs

Do I need to fast?
Yes for FPG/fasting insulin and often lipids; A1c does not require fasting.

A1c vs fasting glucose vs OGTT—what’s the difference?
A1c shows ~3-month average; FPG is a snapshot; OGTT is a challenge test that can uncover early dysglycemia.

What is ApoB and why does it matter?
ApoB counts atherogenic particles; it can refine risk beyond LDL-C.

Should everyone test Lp(a)?
A once-in-lifetime Lp(a) helps refine inherited risk; your clinician will advise.

What is HOMA-IR?
A calculated index from fasting insulin glucose; it informs insulin-resistance risk but isn’t a diagnosis.

How often should I re-check labs when losing weight?
Commonly every 3–6 months for risk factors—timing is clinician-guided.

Can GLP-1 medications change my labs?
They may improve A1c/glucose, weight, and lipids; monitoring cadence is clinician-directed.

What if my ALT is mildly high?
Discuss NAFLD evaluation; FIB-4 helps triage fibrosis risk; imaging decisions are clinician-directed.

Could biotin or anemia affect results?
Yes—biotin may skew some immunoassays; anemia/variants can affect A1c.

References {#references}

  • ADA Standards of Care (diabetes/prediabetes testing: A1c/FPG/OGTT; fructosamine context)

  • ACC/AHA lipid guidance (risk assessment; ApoB, Lp(a), non-HDL-C)

  • AACE/ACE / Endocrine Society (medical care of patients with obesity; pharmacotherapy monitoring—non-directive)

  • AASLD/EASL (NAFLD evaluation; non-invasive fibrosis indices like FIB-4)

  • KDIGO/NKF (kidney risk using eGFR uACR)

  • NIDDK/NIH (weight management basics; A1c caveats)

  • Mayo Clinic Laboratories / ARUP Consult (test utilization, biotin interference, lipid/insulin pre-analytics)

Last reviewed: September 2025 — Medical reviewer: Ulta Lab Tests Medical Review Team

Let's take a look at weight loss lab tests and how they can assist you in losing weight.

To examine your biomarkers and the health of your organs, choose from the list of testing choices below.

Click on the links below to learn more about the effects of being overweight or obese on your health, as well as the lab tests that can help you lose weight and detect, diagnose, and monitor diseases that may be affecting your health.

Browse Weight Management Tests Subcategories

The Key Benefits of Lab Testing in Managing Weight

More and more of us are looking for ways to reduce our weight. The number of Americans struggling with obesity continues to rise, but at the same time, so does the number trying to do something about it. The CDC reported that 17% of Americans are currently on a diet.

Now, many have come to realize that weight management is about way more than calories in and calories out. That's where weight management lab tests come in. They can give us an insight into what's really going on in our bodies.

Let's take a look at weight loss lab tests and how they could help you shed those excess pounds.

What Is the Definition of Obesity?

The CDC uses the Adult Body Mass Index or BMI to define obesity. All you need is your current weight and height, and you can check your BMI using the BMI Index Chart. 

If you have a BMI that is 25.0-30.0, you are classified as overweight. Higher than 30.0 is obese. If your BMI is higher than 40.0, this is called severe obesity.

Learning More About Obesity

Many of us struggle with weight gain as we get older. The pressure of balancing work and family life can make it hard to keep our diets as healthy as we would like. It's easy to neglect regular exercise.

Other factors, including stress, can also affect our ability to lose weight. Stress raises cortisol levels, which can cause our body to hold on to body fat. If you think this might be an issue for you, weight management tests can identify raised levels of cortisol in the bloodstream.

Risk Factors for Obesity

There are multiple risk factors that can lead to an individual struggling with weight management. They can include factors outside our control, such as age, family history, gender, ethnicity, and sex. 

Other factors such as diet, lifestyle, and activity levels also impact our weight.

Causes of Weight Gain

Whether we're battling our genes or not, an unhealthy lifestyle will cause us to gain weight. The most obvious is consuming too many calories, especially from foods that are high in fat, sugar, or both. Not getting enough exercise can also cause us to pile on the pounds.

Less commonly considered are lack of sleep and high levels of stress. Both affect our hormones and can make it harder to control our appetites.

What Are the Signs and Symptoms of Obesity?

There are no specific symptoms of obesity. When checking whether you are overweight or obese, don't rely on BMI alone. It's very important to check waist circumference. 

A high waist circumference is a cause for concern. This can mean a high visceral fat level, leading to many further health complications.

Weight Management Lab Tests

Your first step should be taking a comprehensive look under the hood. A comprehensive metabolic panel (CMP) test looks at your metabolism and how it is functioning. This shows how the body is using food and energy.

This test checks, among other things, how your liver and kidneys are functioning. It can detect abnormal blood sugar levels. Your doctor can use this to detect underlying issues that may be making it difficult for you to lose weight.

Hormone Tests

Hormones related to sex, thyroid function, and stress can greatly impact weight management. The following tests can help you to understand if you have imbalances in these areas:

Elevated or lower-than-normal levels may indicate an underlying condition to your doctor. They can recommend treatment or lifestyle changes that may help to balance your hormones. Once hormone levels are balanced, appetite control and weight loss should become easier.

Early testing can diagnose the beginnings of insulin resistance. If caught early, this can be controlled with lifestyle changes. Weight loss can help to reduce your risk of developing type 2 diabetes.

How Weight Management Tests Are Carried Out

Weight management lab tests can be ordered online. You will take a blood test at an authorized patient service center and then receive the results in a few days, depending on the type of test. After that, you will need to meet with a doctor to help you understand the results.

Your doctor can provide lifestyle advice and treatment options that can help you manage your weight more effectively.

Frequently Asked Questions About Weight Management Lab Tests

Many people haven't previously considered weight loss lab tests as an option for helping them to lose weight. Some of the frequently asked questions include:

  • What are blood tests done for weight loss?
  • Is there a blood test to check metabolism?
  • What tests should be done for weight gain?

A comprehensive set of baseline biomarker tests are the first step. This may give you answers right away. It may also highlight areas that your doctor will want to investigate further. 

Getting these tests is about more than losing weight and looking better. They can detect serious health conditions, such as diabetes, that contribute to metabolic syndrome. The sooner treatment or lifestyle changes are made, the better your chance of reversing these conditions.

Take Control With Weight Loss Lab Tests

Weight loss lab tests can help you to understand your body and how it works best. Along with your physician, you'll be able to find a weight management plan that works for you. They can be your first step on the road to real, long-term weight loss. 

Ulta Lab Tests offers tests that are highly accurate and reliable. They let you make informed decisions about your health. We offer:

  • Secure and Confidential Results
  • No Insurance or Referral Needed
  • Affordable Pricing, including Doctor's Order
  • 100% Satisfaction Guarantee

Order your weight management lab test today. Your results will be provided to you securely and confidentially online in 24 to 48 hours for most tests.

Take charge of your health and track your progress with Ulta Lab Tests.