Short answer
“D” is not a standard lab test name. It is a shorthand. The meaning depends on the panel. On blood work, D often points to vitamin D or D-dimer. On a cannabis certificate of analysis, D9 means delta-9 THC.
Check the panel name, the units, and the reference range. Those three items tell you which D you have.
D on a blood test
Vitamin D
The common vitamin D test is 25-hydroxyvitamin D. Results use ng/mL or nmol/L. A low result means low vitamin D status. A high result means high intake or high sun exposure. The test does not measure the active hormone form.
meaning of d in cannabis products
D-dimer
D-dimer is a protein fragment. The body makes it when a blood clot breaks down. A D-dimer test helps rule out clots. A positive result does not prove a clot. A negative result helps exclude one in low-risk cases.
D9 on a cannabis lab test
Cannabis labs report cannabinoids by name. D9-THC means delta-9-tetrahydrocannabinol. It is the main psychoactive compound in cannabis. COAs often list D9-THC and THCA on separate lines.
Total THC uses a conversion. Total THC = D9-THC + (THCA × 0.877). The 0.877 factor accounts for the loss of a carboxyl group when THCA heats.
D8-THC means delta-8-tetrahydrocannabinol. It is a minor cannabinoid. D10-THC also appears on some panels.
How to read the label
- Find the panel name. “Vitamin D, 25-OH” is blood work. “Cannabinoid potency” is cannabis.
- Check the units. ng/mL and nmol/L fit vitamin D. mg/g or % fit cannabis.
- Check the reference range. Blood tests list a range. Cannabis tests list a result, not a normal range.
When D is unclear
Call the lab. Give the accession number and the panel name. Do not guess from the letter D alone. A single letter can mean different tests on different reports.