A thyroid function test (TFT) checks whether your thyroid gland — the small, butterfly-shaped gland in your neck — is working correctly. Also called a thyroid profile, thyroid panel, or simply a T3 T4 TSH test, it controls your metabolism, energy, weight, mood, and body temperature. Thyroid problems are very common in Pakistan, especially in women, yet they are easy to miss because the symptoms are vague. This guide explains TSH, T3, T4, and the rest of your report in plain language — including what specific combinations like high T4 with low T3, or low TSH with normal T3 and T4, actually mean.
What Does a Thyroid Report Contain?
Pakistani labs offer either a single TSH test or a full thyroid profile. Here are the main values and their typical normal ranges:
| Test | Normal Range (Adults) | What It Measures |
|---|---|---|
| TSH | 0.4-4.0 mIU/L | Pituitary signal telling the thyroid to work — the most important screening value |
| Total T4 (Thyroxine) | 5.0-12.0 µg/dL | Main hormone the thyroid releases |
| Total T3 | 80-200 ng/dL | Active hormone that drives metabolism |
| Free T4 | 0.8-1.8 ng/dL | The unbound, usable form of T4 |
| Free T3 | 2.3-4.2 pg/mL | The unbound, usable form of T3 |
| Anti-TPO antibody | Below 34 IU/mL | Marker of autoimmune thyroid disease (Hashimoto's) |
Reference ranges vary slightly between labs, so always compare your result to the range printed on your own report.
Understanding Your Results: Underactive vs Overactive
High TSH — Underactive Thyroid (Hypothyroidism)
TSH works like a thermostat. When the thyroid is sluggish, the pituitary raises TSH to push it harder — so a high TSH means the thyroid is underactive.
- Symptoms: fatigue, weight gain, feeling cold, dry skin, hair fall, constipation, low mood, irregular periods.
- Subclinical hypothyroidism: high TSH but normal T4 — often just monitored or treated in pregnancy.
- Overt hypothyroidism: high TSH with low T4 — usually treated with thyroxine (levothyroxine) tablets.
Low TSH — Overactive Thyroid (Hyperthyroidism)
A low TSH usually means the thyroid is overactive, producing too much hormone.
- Symptoms: weight loss despite normal eating, fast or pounding heartbeat, anxiety, tremors, sweating, heat intolerance, frequent stools.
- Confirmation: low TSH with high T4 and/or T3 confirms hyperthyroidism and needs specialist evaluation.
Anti-TPO — The Autoimmune Marker
A high Anti-TPO antibody suggests Hashimoto's thyroiditis (the most common cause of hypothyroidism) or Graves' disease. It explains why the thyroid is misbehaving even when the hormone levels are still borderline.
Common Patterns Doctors Look For
| Pattern | What It Suggests | Next Steps |
|---|---|---|
| High TSH + Low T4 | Hypothyroidism (overt) | Start thyroxine, recheck in 6-8 weeks |
| High TSH + Normal T4 | Subclinical hypothyroidism | Monitor, check Anti-TPO |
| Low TSH + High T4/T3 | Hyperthyroidism | Specialist referral, further workup |
| High TSH + High Anti-TPO | Hashimoto's thyroiditis | Treat hypothyroidism, monitor long term |
| Normal TSH | Thyroid function likely normal | No action unless symptoms persist |
What Do Specific T3, T4, and TSH Combinations Mean?
People often read one hormone in isolation and worry. In reality, TSH, T4, and T3 only make sense read together. Here is what the specific combinations most people search for actually indicate:
| TSH | T4 | T3 | What It Usually Means |
|---|---|---|---|
| Normal | Normal | Normal | Healthy thyroid function |
| High | Low | Low/Normal | Overt hypothyroidism (underactive) |
| High | Normal | Normal | Subclinical hypothyroidism |
| Low | High | High | Overt hyperthyroidism (overactive) |
| Low | Normal | Normal | Subclinical hyperthyroidism (mild overactivity) |
| Low/Normal | High | Low | Reduced T4-to-T3 conversion (often illness or medication) |
| Normal | Normal | Low | Low-T3 syndrome (common during any serious illness) |
What "High T4, Low T3" Means
Your body converts T4 (the storage hormone) into T3 (the active hormone) as it needs it. When T4 is high or normal but T3 is low, it usually means that conversion is being slowed down rather than a thyroid gland problem. The most common reasons are:
- Any serious or acute illness — infection, surgery, or hospitalization lowers T3 first. This is called low-T3 (sick euthyroid) syndrome and usually corrects itself once you recover.
- Certain medicines — beta-blockers like propranolol, steroids, and amiodarone can block T4-to-T3 conversion.
- Early thyroid treatment or starvation/crash dieting.
Because a high T4 with low T3 is rarely a primary thyroid disease on its own, it should always be interpreted alongside your TSH and how you feel. If TSH is normal, the thyroid gland itself is usually working fine.
What "Low TSH with Normal T3 and T4" Means
A low TSH while T3 and T4 are both still normal is called subclinical hyperthyroidism — a mild, early form of an overactive thyroid. The pituitary has sensed slightly too much thyroid hormone and dialed TSH down, but hormone levels haven't yet risen above range. It is often mild and monitored rather than treated immediately, but it can also be caused by too high a dose of thyroxine tablets, early Graves' disease, or thyroid nodules, so it's worth a repeat test and a doctor's review.
How Much Does a Thyroid Test Cost in Pakistan?
| Test | Approximate Price (2026) |
|---|---|
| TSH only | Rs. 800-1,500 |
| TSH + Free T4 | Rs. 1,500-2,500 |
| Full thyroid profile (TSH, T3, T4) | Rs. 2,000-4,000 |
| Anti-TPO antibody | Rs. 1,500-3,000 |
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Try MedVault Free →Frequently Asked Questions
What is a thyroid function test (TFT)?
A thyroid function test measures how well your thyroid gland is working. The main values are TSH, T4, and T3, sometimes with Free T4, Free T3, and Anti-TPO antibodies. It detects hypothyroidism, hyperthyroidism, and autoimmune thyroid disease. A TSH test costs around Rs. 800-1,500 in Pakistan.
What is the normal TSH range?
The normal TSH range is roughly 0.4 to 4.0 mIU/L for most adults. High TSH suggests an underactive thyroid; low TSH suggests an overactive thyroid. Pregnant women have different targets, so check the range on your own report.
What does a high TSH mean?
High TSH (above 4.0 mIU/L) usually means an underactive thyroid (hypothyroidism). Symptoms include fatigue, weight gain, feeling cold, and hair fall. High TSH with low T4 usually needs thyroxine treatment.
How common are thyroid problems in Pakistan?
Thyroid disorders are very common in Pakistan, especially in women, who are several times more likely than men to be affected. Because symptoms are vague, many cases stay undiagnosed until a TSH test is done.
What is the normal level of T3, T4, and TSH?
For most adults: TSH 0.4-4.0 mIU/L, total T4 5.0-12.0 µg/dL, total T3 80-200 ng/dL, Free T4 0.8-1.8 ng/dL, and Free T3 2.3-4.2 pg/mL. Ranges vary slightly by lab, so compare each value to the range on your own report.
What does a low TSH mean?
A low TSH (below 0.4 mIU/L) usually means an overactive thyroid. With high T4/T3 it is overt hyperthyroidism; with normal T4/T3 it is subclinical hyperthyroidism, which is milder and often monitored. Too high a dose of thyroxine tablets can also lower TSH.
What does high T4 and low T3 mean?
High or normal T4 with low T3 usually means the body is converting less T4 into active T3 — most often due to a serious illness (low-T3/sick euthyroid syndrome), medicines like beta-blockers or steroids, or crash dieting, rather than a thyroid disease. If TSH is normal, the gland itself is usually fine.
What does low TSH with normal T3 and T4 mean?
This is subclinical hyperthyroidism — a mild, early overactive thyroid where TSH has dropped but T3 and T4 are still normal. It's often monitored with a repeat test, but can be caused by too high a thyroxine dose, early Graves' disease, or nodules, so see a doctor.