The phrase "assay instruction" is correct and usable in written English.
It can be used in contexts related to scientific or laboratory procedures, particularly when referring to guidelines for conducting assays.
Example: "Before starting the experiment, please review the assay instruction to ensure accurate results."
Alternatives: "assay guidelines" or "assay protocol".
Sample preparation, dilution and enzyme detection were performed according to the specific assay instructions.
The genotyping reactions were performed according to the standard Illumina GoldenGate assay instructions (http://www.illumina.com).
All SNP markers were genotyped on a GoldenGate array platform according to the standard Illumina GoldenGate assay instructions (http://www.illumina.com).
PCR cycles were performed according to the assay instructions in an ABI PRISM® 7000 Sequence Detection System (Applied Biosystems).
Urine, serum, and renal IL-6 were measured by ELISA using a species specific (that is, mouse or human) kit according to assay instructions (R&D Systems).
All IGF-I measurements were performed on the iSYS IGF-I immunoassay using the supplied reagents and following the manufacturer's assay instructions [further assay details have been published previously by Bidlingmaier et al. (Bidlingmaier et al., 2014)].
Urine IL-6, IL-8, IL-10, IL-1β, and TNF-α were measured in duplicate using human ELISA kits according to assay instructions (R&D Systems, Minneapolis, MN, USA).
As recommended by the Salimetrics assay instructions, for each participant the level of each hormone was calculated as the mean over the values assessed in three samples that were collected over the course of the experiment (see Procedure).
After treatment the cells were washed twice with phosphate-buffered saline, lysed, the lysates analyzed as per kit instructions and the results normalized to the average protein content of 33μg/mll (determined on 10-fold dilution of lysates as per Bio-Rad protein assay instructions).
The concentrations of the neuropeptides BN/GRP and SP (in serum) and of the neuropeptides CGRP, NPY, and VIP (in joint fluid and serum) were measured using Enzyme Immunoassay kits (Phoenix Pharmaceuticals, Belmont, CA, USA) in accordance with the supplier's assay instructions.
