About the ZRT Laboratory at-home blood spot test

Using a blood spot test to measure the amount of vitamin D in your blood is an accurate way to discover if you are getting enough vitamin D. The blood spot test from ZRT Laboratory is called a 25(OH)D test.

ZRT Laboratory, in partnership with the Vitamin D Council, offers an at-home 25(OH)D blood spot test. The test is simple and convenient. Most importantly, the results are extremely accurate and will tell you if you’re getting enough vitamin D. 

How the ZRT Laboratory test works:

  1. Order a test, which will be shipped to your home.
  2. The test kit provides everything you need; the test requisition, alcohol prep pad, return packaging, lancets, sterile gauze pad, blood spot card, and an adhesive bandage. 
  3. Follow the finger prick instructions on the instruction card included inside your kit to ensure you correctly collect your blood spot sample. 
  4. Fill out the requisition form and place form along with your blood spot card into the return envelope. 
  5. Mail return envelope to ZRT Laboratory. If you live in the United States, the envelope is pre-paid and there are no return shipping costs.
  6. ZRT Laboratory will email your results to you within one week. Your results can also be mailed to you in a hard copy if you prefer. 

Support the Vitamin D Council

15% of the proceeds from the sale of each ZRT Laboratory vitamin D test are donated to the Vitamin D Council. As the Council is a nonprofit organization, this is a great way to get involved in your health and support the organization at the same time.

Interpreting your results

The Vitamin D Council has several informational pages to help you interpret your results. See the following pages:


  • By ordering this test, I agree and understand that I have not entered into a doctor-patient relationship with Executive Director of the Vitamin D Council, John Cannell, MD, who provides the doctor’s order for the 25(OH)D test.
  • I understand that Dr. Cannell is not my doctor
  • I understand the vitamin D kit I am buying will report my 25(OH)D level to me. What actions I do or do not take after getting the results back is up to me and my doctor, not Dr. Cannell or the Vitamin D Council. 
  • California disclaimers regarding testing do not apply.
  • New York State health law prohibits the testing of specimens collected in or mailed from New York and prohibits the transmission of data from our laboratory to NY physicians or residents. Therefore, ZRT is unable to process such orders at this time.  

Shipping & Return Policies

No PO Boxes - a physical address is required for delivery. Orders typically ship within two business days but date and time of order shipment or delivery is not guaranteed. Requests for Overnight delivery must be received by 11am Pacific Time to ship the same day, does not include weekends or holidays and may not be available to all areas. It is the receiver's responsibility to pay any sales and/or country taxes, international import fees and custom duties. NY residents: Due to special restrictions, no orders will be shipped to the state of NY.Estimated delivery times do not include weekends or holidays. Ground 5-7 days, 2-Day 2 days (Puerto Rico must use this option), Next Day 1 day, International (incl. Canada) 5-10 weekdays. Shipping fees are non-refundable. The original test kit, including all contents and the original Test Requisition must be returned to ZRT Laboratory before any refunds can be issued.