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Optimum results are obtained from samples with <100mg/dL Hemoglobin concentration in serum (refer to Mayo Clinic chart here)


Lipemic samples for 25OH Vitamin D are preferably analyzed by RIA due to required sample volumes (25-50 ul)

25OH Vitamin D for general nutritional status

1,25(OH)2 Vitamin D for renal disease, sarcoidosis, hyperparathyroidism, Vitamin D resistant rickets (generally in felines)

Total Serum Vitamin D2 and/or Vitamin D3 - experimental supplementation with Vitamin D2, Vitamin D3, or suspected Vitamin D toxicity.

Vitamin D2 or Vitamin D3 in foods, feeds, and supplements - Contact us for additional analyses offered.

Vitamin D and Vitamin D metabolites circulate in the body bound to the Vitamin D binding protein, which keeps the metabolites stable and prevents degradation. Therefore, samples remain viable at room temperature for several days, and when stored frozen, Vitamin D metabolites are stable for years and will withstand up to three freeze thaw cycles. Parathyroid hormone is labile though and needs to be analyzed on the first freeze/thaw cycle.

Generally it is not necessary to differentiate the two forms. The total 25OH Vitamin D is the important measurement and is the best indicator of Vitamin D status. A recent report suggested that reporting separate values for 25OH Vitamin D2 and 25OH Vitamin D3 confused some clinicians. However, if a clinical trial involves the use of Vitamin D2 as a supplement, the scientist may wish to have each form identified to monitor their contribution to the total 25OH Vitamin D.

We will either return or discard your samples as indicated by the client on the purchase order form.  Please be sure to fill out the form with your shipping company, account number, and destination address.  If these items are not provided we will discard samples 30 days after results have been sent out.

Download our samples shipping requirements document here.

*For all Liaison XL work, samples should be sent in one of the following test tubes:

  1. 12x75 plastic tube #110441 
  2. 2.0 mL cryotube #AV-2345-S0 (MidSci)
  3. 0.5 mL #AV-2125-S0 (MidSci)


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