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Quantification of the Immunosuppressant Tacrolimus on Dried Blood Spots Using LC-MS/MS

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Vitamin B6 in plasma - sample stability and the reference limits.

Kristine K Panton¹, Per G Farup, Erling Sagen

¹Department of Medical Biochemistry, St. Olav's Hospital, Trondheim University Hospital , Trondheim.

Scandinavian Journal of Clinical and Laboratory Investigation

|July 4, 2013

Summary

Pyridoxal-5'-phosphate (p-PLP), the primary vitamin B6 form in plasma, has established reference intervals and demonstrated stability. This ensures reliable p-PLP measurements for assessing nutritional status in patients.

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Published on: March 13, 2015

Area of Science:

Biochemistry
Clinical Chemistry
Nutritional Science

Background:

Pyridoxal-5 '-phosphate (p-PLP) is the most abundant vitamin B6 vitamer in human plasma.
Accurate p-PLP measurements are crucial for assessing nutritional status, especially in vulnerable patient populations.
Establishing reliable reference intervals and understanding sample stability are prerequisites for clinical utility.

Purpose of the Study:

To determine the reference interval for p-PLP in healthy adults.
To assess the stability of p-PLP in plasma samples under various storage conditions.
To validate p-PLP measurement for clinical use in nutritional assessment.

Main Methods:

Blood samples were collected from healthy blood donors.
p-PLP concentrations were quantified using high-performance liquid chromatography (HPLC).
Sample stability was evaluated over 24 hours at room temperature and refrigerated (4-8°C).

Main Results:

The reference interval for p-PLP in adults was determined to be 23-223 nmol/L.
p-PLP remained stable in plasma samples for 24 hours at both room temperature and 4-8°C.
These findings support the feasibility of using p-PLP measurements in routine clinical practice.

Conclusions:

The established reference interval provides a benchmark for p-PLP levels in healthy individuals.
The demonstrated stability of p-PLP under common storage conditions facilitates reliable diagnostic testing.
p-PLP measurement is a viable tool for nutritional status assessment, even with standard specimen transport times.