The phrase "ascertained by using an" is correct and usable in written English.
It can be used when describing a method or process through which something is determined or verified.
Example: "The results of the experiment were ascertained by using an advanced statistical analysis."
Alternatives: "determined through the use of" or "verified by employing a".
Exposure assessment was ascertained by using a geographic information system to link the study subjects to specific water supplies.
By excluding individuals residing in assisted living facilities, we minimized the possibility of recruiting older women with significant cognitive impairment, as further ascertained by using a dementia screener.
Familial recurrence of melanoma was ascertained by using a questionnaire to interview probands about their first-, second-, and third-degree relatives.
Approximate timing of infection for patients with IgG-positive samples was ascertained by using a commercial solid-phase enzyme immunoassay (Toxoplasma gondii IgG Avidity EIA; Ani Labsystems Ltd. Oy, Vantaa, Finland) to determine avidity (binding ability) index.
The information on CVD mortality and morbidity were collected from National Causes of Death Register and the National Hospital Discharge Registry and ascertained by using a computerized record linkage of individual ID numbers of each of the individuals participating in the study.
The presence of this species was ascertained by using a 5S 23S spacer amplicon after digestion with MseI and demonstration of fragments having sizes typical for B. spielmanii (106, 68, and 51 bp) (2 ).
The involvement of activated AR in the androgen-dependent regulation of DAX-1 was ascertained by using a shRNA interfering approach able to cause a reduction in AR expression in MCF-7 cells that can be particularly appreciated in the nuclear compartment.
Lack of genomic and foreign DNA contamination was ascertained by using all RNA samples and water as a template in a PCR.
Lack of genomic and foreign DNA contamination was ascertained by using all RNA samples and water as a template in a PCR reaction.
