Lab tests
How to read your vitamin D blood test results
A vitamin D report often carries a long chemical name, one of two possible units, and a table of bands such as deficient, insufficient and sufficient that is not the same from one laboratory to the next. Add your report below to see which number is which and how your own laboratory labelled it.
Explain your vitamin d test
- 1. Add itDrop a PDF, take a photo or paste the text.
- 2. Check itPersonal details are removed on your device. You approve what is sent.
- 3. Read itSummary, table of results, terms and questions to ask.
The explainer opens on its own page with no adverts and no outside scripts. Your file is read on your device and is never uploaded.
What you get
- The total 25-hydroxyvitamin D result on its own row, with D2 and D3 shown separately if your report splits them.
- The unit your report uses, ng/mL or nmol/L, named so the number is not read on the wrong scale.
- The laboratory's own bands or reference range restated as printed.
- Questions to ask the clinician who ordered the test.
Lines you may see on a vitamin D report
- 25-hydroxyvitamin D, also written 25(OH)D or calcidiolThe form of vitamin D usually measured in a blood test
- Vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol): the two forms of vitamin D, which some laboratories report separately
- Total 25-OH vitamin DThe D2 and D3 figures added together
- 1,25-dihydroxyvitamin D (calcitriol)The active form of vitamin D, which is a different and less often ordered test
- ng/mL and nmol/LTwo units for the same measurement
- Calcium, phosphate and PTH (parathyroid hormone)Related tests that are sometimes reported on the same page
What this tool cannot tell you
Laboratories and guidelines do not agree on a single set of vitamin D bands, so the same number can sit under different labels on different reports. Results can also vary with the season and with the method the laboratory used. MedicDecode restates the bands printed on your own report and explains the terms. It does not say whether you need a supplement or how much to take; that is a question for your clinician.
Common questions
Why does my report show both D2 and D3?
They are two forms of vitamin D. Some laboratory methods measure each one separately and print both alongside a total, while others report a single combined figure.
My result is in nmol/L but an earlier one was in ng/mL. Can I compare them?
Not directly. They are different units for the same measurement, so the two numbers are on different scales. The explanation uses the unit and the range on the report you add; ask your clinician or the laboratory if you need two reports compared.
Will it tell me how much vitamin D to take?
No. MedicDecode does not give supplement or dosing advice. Your doctor or pharmacist can tell you whether a supplement is appropriate for you.
Words you may see on this report
Tap a word for its plain-English meaning, an example line and what it does not mean.
- ALT (Alanine Aminotransferase)
ALT is an enzyme found mainly in the liver; when liver cells are irritated or damaged, more ALT leaks into the blood.
- AST (Aspartate Aminotransferase)
AST is an enzyme found in the liver, muscles, heart and other tissues; raised levels can signal stress or damage in one of these.
- Bilirubin
Bilirubin is a yellow substance made when old red blood cells break down; the liver processes it so it can leave the body.
- Creatinine
Creatinine is a waste product from normal muscle activity that the kidneys filter out, so its blood level helps show how well the kidneys work.
- CRP (C-Reactive Protein)
CRP is a protein made by the liver that rises quickly when there is inflammation or infection in the body.
- Culture and Sensitivity
A culture and sensitivity test grows germs from a sample to identify them, then checks which antibiotics can stop them.
- eGFR (Estimated Glomerular Filtration Rate)
eGFR is an estimate of how well your kidneys filter waste from your blood, calculated from a creatinine blood test plus details like age.
- Electrolytes
Electrolytes are minerals in the blood, such as sodium, potassium and chloride, that carry an electric charge and help the body work.
- ESR (Erythrocyte Sedimentation Rate)
ESR measures how fast red blood cells sink in a tube of blood over an hour; a faster rate can be a general sign of inflammation.
- Fasting Sample
A fasting sample is blood taken after you have had nothing to eat or drink except water for a set number of hours.
- Ferritin
Ferritin is a protein that stores iron; its blood level gives a good idea of how much iron the body has in reserve.
- HbA1c
HbA1c shows your average blood sugar over roughly the past two to three months by measuring how much sugar is attached to red blood cells.