The phrase "ascertained only through" is correct and usable in written English.
It can be used when discussing methods or processes by which something can be determined or verified.
Example: "The results of the experiment can be ascertained only through careful analysis of the data collected."
Alternatives: "determined solely by" or "verified exclusively through".
To do that one needs a certain wisdom that is only ascertained through years of first-hand experience, and I am very much still learning the ropes myself.
In conclusion, homozygous and compound-heterozygous mutations in ZFP57 cause a human imprinting syndrome as yet only ascertained through presentation with TNDM1.
Certainly, the exact position of the eyeball can only be ascertained through three-dimensional analysis.
This is something that will need further testing, as the likelihood that it is a true null effect can only be ascertained through a programmatic approach of attempts to reject the null, such as the current study.
As other studies are addressing the factors that can only be ascertained through questionnaires, there is less impetus to have a further study addressing the same issues.
Thus, NTFD provides a straightforward framework for combining the systems-level capabilities of traditional metabolomics approaches with the kinetic information that can only be ascertained through the use of isotopic tracers.
Because HSV-2 is incurable and frequently asymptomatic, this exposure can only be accurately ascertained through HSV type-specific serologic assays that detect antibody to glycoprotein G. Studies using less accurate serologic assays such as those based on whole virus or crude antigen preparations were excluded.
In USRDS, only 1% of deaths are ascertained through national vital statistics [ 2].
However, studies of arsenic contamination and CHD in Bangladesh have hitherto been limited, so far comprising a single report involving only about 100 CHD outcomes ascertained through verbal autopsy [ 28].
