Urine TGF- β1 Assay Validation: Spinning Down Urine Samples Could Diminish TGF-β1 Signal

Pavlov, I.Y.; Shihab, F.; Delgado, J.C.

Clinical Laboratory 57(11-12): 1027-1029

2011


ISSN/ISBN: 1433-6510
PMID: 22239038
Document Number: 15932
Background: TGF-β1 is a mediator of immune and anti-inflammatory responses. The present research was dedicated to the validation of the urine Quantikine Human TGF-β1 ELISA assay. Methods: A reference interval was developed utilizing 100 urine samples from healthy donors. Samples containing precipitate were centrifuged and supernatants or unspun specimens were run with TGF-β1 assay. Results: Supernatant TGF-β1 concentrations are only a fraction of the unspun sample values (77 % to 29 %, even less for the low concentration samples). Validation involving uncentrifuged urine samples demonstrated the following TGF-β1 assay characteristics: linearity from 23 to 1286 pg/mL, recovery from 95 to 116 %; precision: <17 %; analytical specificity 3 pg/mL; reference interval from 0 to 39 pg/mg creatinine; freeze-thaw stability: af-ter first thawing, urine samples could loose from 5 to 40 % of TGF-β1 activity on each following freeze-thaw circle. Conclusions: For TGF-β1 assay, urine sample preparation should not include a centrifugation step; repeating freeze-thawing should be avoided.

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Urine TGF- β1 Assay Validation: Spinning Down Urine Samples Could Diminish TGF-β1 Signal