I had used Angiotensin II EIA Kit cat.no. RAB0010 from SIGMA but the results are confusing... I cannot understand why standart curve must be built by 1,000 pg/ml, 100 pg/ml, 10 pg/ml, 1 pg/ml, 0.1 pg/ml, and 0 pg/ml and according kit's typical data must have approximately 100% absorbance for three of the standard: 10 pg/ml, 1 pg/ml, 0.1 pg/ml. Can someone share what quantity of Angiotensin II is expected or observed in normal serum samples?
Hi Lyuba, You are right. The mentioned subject is a disadvantage of Sigma AngII EIA kit. As you know methodologically for quantitative assay, we must have standard points. assay range is related to amount between lowest and highest standard point. And assay sensitivity is less/equal the first standard point or minimum standard point amount. But in Sigma AngII EIA kit, the minimum standard point concentration is 0.1 pg/ml and the second point is 1 pg/ml but the assay sensitivity is 2.6 pg/ml.
Assay sensitivity means, the assay can not determine any amount below that. and assay range means that you can determine any concentration between assay rang. And this is inconsistency in the assay kit. It is logical when the assay can not determine any concentration less than 2.6 pg/ml, the B/B0% for lower amount such as 0.1 and 1 pg/ml be around 100%.
best
mehdi
Thank you Mehdi Hedayati! Can you share what is the expected concentration of Angiotensin II in normal human serum samples?
All the best
Lyuba
Dear Lyuba, as you know in different study with different methods, a wide rang reported as normal or expected human serum/plasma Ang-II value. But in my expertience, it is around 15pg/ml +- 4pg/ml.
regards
mehdi
Once again, thank you very much!!I Your answers are very helpful for me!!!
All the best !!!
Lyuba
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