LabInformationLab tests, explained

TSH Blood Test in California

This page explains the tsh blood test, what it measures, and how to arrange it. A TSH blood test measures thyroid-stimulating hormone, a signal from your pituitary gland that tells your thyroid how much hormone to make. It is ordered to check for an underactive or overactive thyroid and to monitor thyroid treatment. Across California, part of Pacific, the tsh blood test can be ordered directly and collected at a certified site — no referral required.

Sample type
blood
Category
Hormone
Turnaround
1-3 business days
Price
$39
Referral
Not required

A TSH blood test measures thyroid-stimulating hormone, a signal from your pituitary gland that tells your thyroid how much hormone to make. It is ordered to check for an underactive or overactive thyroid and to monitor thyroid treatment.

What it measures

  • TSH (thyroid-stimulating hormone) — The main marker; high or low levels can suggest thyroid problems.
  • Free T4 (thyroxine) — Sometimes added to see how much active thyroid hormone is available.
  • Free T3 (triiodothyronine) — Less often checked; helps assess thyroid function in some cases.
  • Thyroid antibodies — May be tested if autoimmune thyroid disease is suspected.

Who it is for

A healthcare provider typically orders a TSH test if you have symptoms like fatigue, weight changes, or a fast or slow heartbeat, or to monitor thyroid medication.

Preparation

No fasting is usually required. Tell your provider about any thyroid medicines or supplements you take, as timing may matter.

Results and what they mean

Results are reported as a number with a reference range. Your clinician interprets the result along with your symptoms and history. This is general information, not medical advice; discuss your results with a qualified healthcare professional.

Requesting the TSH Blood Test in California

Order online, choose a certified collection site in California, and review results through a secure portal. No referral is required, and orders are processed confidentially. Access across Pacific is uneven, so confirming a site ahead of time is worthwhile.

Frequently asked questions

Do I need to fast for a TSH test?

No, fasting is not typically needed. You can eat and drink normally unless your provider gives other instructions.

What can affect my TSH level?

Thyroid medicines, biotin supplements, pregnancy, and some other medications can affect results. Share all supplements and medicines with your provider.

How soon will I get my results?

Most results are available within 1–3 business days, but this can vary by lab.

Can I take my thyroid medication before the test?

Ask your provider. Some recommend taking it after the blood draw, while others say it does not matter.

TSH Blood Test by city in California

All testing in California →   Full TSH Blood Test guide →