Thyroid Test India: T3, T4, TSH, Anti-TPO — Which Test Do You Need & What It Costs

Your doctor has told you to "get a thyroid test." You arrive at the lab and are handed a form with six options: TSH, T3, T4, Free T3, Free T4, Anti-TPO, Anti-thyroglobulin. Which ones do you actually need?

For most people, the answer is one or two. But the right combination depends entirely on what your doctor is trying to find out. This guide explains every thyroid test used in India — what it measures, when it is appropriate, what a normal result looks like, and what it costs.

Key Takeaways:

• TSH alone is the correct screening test for almost all thyroid conditions
• TSH + Free T4 is the standard pair for diagnosing and monitoring hypothyroidism
• Anti-TPO is the test that tells you why the thyroid is failing — it detects autoimmune thyroid disease (Hashimoto's, Graves')
• T3 (total or free) is rarely needed for routine monitoring — it is ordered for specific situations
• India-specific: Thyroid disorders are extremely common in India — hypothyroidism affects an estimated 10–15% of women

1. Which Thyroid Test Do You Need?

Tell us your situation and we will show you which thyroid tests are typically ordered for it.

This is a general guide. Your doctor decides which tests are appropriate based on your specific clinical situation.

2. The Complete Thyroid Test Guide

TSH — Thyroid Stimulating Hormone

What it measures: TSH is produced by the pituitary gland to tell the thyroid to produce hormones. When the thyroid is underactive (hypothyroidism), TSH rises trying to stimulate it. When the thyroid is overactive (hyperthyroidism), TSH falls as the pituitary senses excess thyroid hormone.

TSH is the body's most sensitive indicator of thyroid status — it changes before T3 or T4 move outside their normal range.

Normal range: 0.4–4.0 mIU/L (standard adult). Pregnancy-specific ranges differ significantly — see below.

When TSH alone is enough: Routine screening, follow-up of stable hypothyroid patients on established thyroxine dose, annual thyroid check in an asymptomatic person.

When TSH alone is NOT enough: New abnormal TSH (add Free T4), symptoms suggest hyperthyroidism, pregnancy (trimester-specific ranges needed), suspected thyroid cancer (add thyroglobulin).

For a deep dive on TSH normal ranges and interpretation: TSH Normal Range India — Complete Guide

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Free T4 (FT4) — Free Thyroxine

What it measures: Thyroxine (T4) is the main hormone produced by the thyroid gland. Most T4 in the blood is bound to proteins — "Free T4" is the unbound, biologically active fraction that actually enters cells. Free T4 is more accurate than total T4 for most clinical purposes.

Normal range (India): 0.8–1.8 ng/dL (or 10–23 pmol/L)

When to order: Whenever TSH is abnormal (to confirm and quantify the thyroid problem), when hypothyroidism treatment is being adjusted, during pregnancy monitoring.

Cost in India: ₹300–₹600 at most private labs

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Total T4 (TT4)

Total T4 measures both bound and free thyroxine combined. It is less commonly ordered now because Free T4 is more accurate — binding proteins (affected by pregnancy, oral contraceptives, liver disease) distort total T4 results without reflecting actual thyroid function.

When it may still be ordered: Some older doctors or smaller labs still use total T4 as a cost-effective alternative. The Indian government hospital formulary at some centres uses total T4 rather than free T4.

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Free T3 (FT3) — Free Triiodothyronine

What it measures: Triiodothyronine (T3) is the active thyroid hormone that actually enters cells and drives metabolism. Most T3 is converted from T4 in the body's peripheral tissues, not produced directly by the thyroid.

Normal range (India): 2.0–4.4 pg/mL (or 3.1–6.8 pmol/L)

When FT3 is ordered:

• T3 toxicosis: A rare form of hyperthyroidism where T4 is normal but T3 is elevated — classic in toxic multinodular goitre
• Monitoring amiodarone therapy (the cardiac drug strongly affects T3/T4 conversion)
• Non-thyroidal illness syndrome: Sick patients often have low T3 — assessment of this pattern
• Monitoring conversion in treated hypothyroid patients on T4-only therapy who still have symptoms

T3 is NOT needed for: Routine hypothyroid monitoring. Routine screening. Most hyperthyroidism cases (TSH + FT4 usually sufficient). Ordering T3 "just to be complete" adds cost without clinical value in most scenarios.

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Anti-TPO Antibodies (Anti-Thyroid Peroxidase)

What it measures: Antibodies produced by the immune system against thyroid peroxidase — an enzyme essential for thyroid hormone production. A high Anti-TPO means the immune system is attacking the thyroid.

Normal range: < 35 IU/mL (some labs use < 34 or < 60 depending on assay)

What a positive Anti-TPO means:

• Hashimoto's thyroiditis: The most common autoimmune thyroid disease in India — the immune system gradually destroys the thyroid, eventually causing hypothyroidism. Anti-TPO is positive in 90–95% of Hashimoto's cases.
• Graves' disease: Autoimmune hyperthyroidism — Anti-TPO positive in about 75% of cases
• Postpartum thyroiditis: Immune attack on the thyroid after delivery

Why this matters clinically:

• Subclinical hypothyroidism (high TSH, normal FT4) with positive Anti-TPO is much more likely to progress to overt hypothyroidism — many endocrinologists start treatment earlier in this group
• Pregnant women with Anti-TPO positive have higher risk of miscarriage, preterm delivery, and postpartum thyroiditis — close monitoring is essential
• Positive Anti-TPO explains the cause of the thyroid abnormality — helpful for prognosis and family counselling

Cost in India: ₹500–₹1,200 at private labs

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Anti-Thyroglobulin (Anti-TG) Antibodies

What it measures: Antibodies against thyroglobulin — the protein the thyroid uses to store T3/T4.

Normal range: < 115 IU/mL

When ordered: Often alongside Anti-TPO when autoimmune thyroid disease is suspected. Anti-TG alone has lower sensitivity than Anti-TPO for Hashimoto's (positive in only 70% of cases versus 95% for Anti-TPO). Anti-TG is also used after thyroid cancer surgery to monitor for recurrence (in this context, both thyroglobulin and Anti-TG are tracked).

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3. Complete Thyroid Test Cost in India

Practical tip: If your doctor orders "thyroid profile," confirm whether this means T3+T4+TSH (total — older, less accurate) or TSH+FT4 (free, preferred). The total panel is cheaper but gives less clinically precise information for T4.

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4. Thyroid Testing in Pregnancy — Different Rules

Thyroid function changes significantly during pregnancy and the standard adult TSH reference range does not apply.

Trimester-specific TSH reference ranges (Thyroid Association of India / ATA):

A TSH of 3.2 mIU/L is "normal" for a non-pregnant adult but falls above the target range in early pregnancy — and maternal hypothyroidism affects fetal neurological development. Every pregnant woman should have TSH checked at the first antenatal visit.

Also order Anti-TPO in pregnancy if: TSH is borderline/elevated, personal or family history of thyroid disease, previous thyroid surgery or radioiodine, type 1 diabetes, prior pregnancy loss.

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5. Thyroid Test Guide by Scenario

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6. People Also Ask

Is T3 T4 TSH test different from thyroid profile?

"Thyroid profile" at most Indian labs means T3 + T4 + TSH (using total, not free fractions). This is the older, less accurate test set. The preferred modern panel is TSH + Free T4 (or TSH + Free T4 + Free T3 if hyperthyroidism is suspected). Ask your lab which fractions they measure when you see "thyroid profile."

Which thyroid test to do first?

Always start with TSH. It is the pituitary's signal to the thyroid — the most sensitive early indicator of any thyroid problem. If TSH is normal, no further testing is usually needed for routine screening.

Does thyroid test require fasting?

No. TSH and thyroid hormone levels are not affected by food intake. You can eat and drink normally before a thyroid test. However, if the thyroid test is part of a larger panel that includes fasting glucose or lipids, those require fasting.

What does "subclinical hypothyroidism" mean?

Subclinical hypothyroidism means TSH is elevated (typically 4–10 mIU/L) but Free T4 is still within the normal range. Whether to treat it depends on the level, symptoms, age, pregnancy status, and Anti-TPO result. This is an active area of clinical debate — some doctors treat TSH > 4.5, others wait until > 10.

7. Conclusion

The thyroid testing landscape in India is confusing partly because different labs use different panels, different reference ranges, and older vs. newer methodologies. The framework is simple: start with TSH, add Free T4 if TSH is abnormal, add Anti-TPO when you need to know the cause. T3 testing is specific and not routine.

Store every thyroid report in Ayu with the exact date, lab name, and reference range printed on the report. TSH varies by lab assay — comparing your 2022 Thyrocare result to your 2026 Apollo result directly can mislead. Storing the full report (not just the number) preserves the context.

8. Medical Disclaimer

This article is educational. Thyroid test interpretation must be done by a qualified clinician with full clinical context. Reference ranges printed on your lab report are the authoritative ranges for that specific assay — not the generic values in this guide.