Powershell decimal to [Int] not failing

Question

I am trying to validate a string of what should be comma separated integer values to use as success codes. If I start with an array with some invalid values, like this...

$test = @(0, 100, -200, 3.3, 'string')
foreach ($item in $test) {
    if ($item -isnot [Int]) {
        Write-Host "![Int] $item"
    } else {
        Write-Host "[Int] $item"
    }
}

I get the expected results, the first three are [Int] and the last two are not.

However, if I start from a string and build the array, like this

$testString = '0, 100, -200, 3.3, string'
$test = $testString.Split(',').Trim()

then all tests are not [Int], which makes sense because the array will be strings. I need to cast to [Int] first. But when I do, like this

$testString = '0, 100, -200, 3.3, string'
$test = $testString.Split(',').Trim()
foreach ($item in $test) {
    if ($item -as [Int] -isnot [Int]) {
        Write-Host "![Int] $item"
    } else {
        Write-Host "[Int] $item"
    }
}

3.3 is returning as [Int]. I found this which clues me in that casting is too smart for what I am trying to do it seems. So, IS there a way to cast a decimal to int and get a failure, or do I need two conditionals, one to cast and catch the true strings, and one to look for . and thus find the decimals? Or perhaps to compare the value of [Int] with a cast to [Single] like this?

$testString = '0, 100, -200, 3.3, string'
$test = $testString.Split(',').Trim()
foreach ($item in $test) {
    if ($item -as [Int32] -isnot [Int32]) {
        Write-Host "![Int] $item"
    } else {
        Write-Host "[Int] $item"
    }
}

This is the most elegant way I have managed to get to work, but I wonder if there is actually a better approach? I also tried if ([Int]$item -isnot [Int]) {, which is I think an actual Cast, while -as is technically Coercion, and that still fails to catch the decimal, while throwing an error on the string. So I am left thinking I understand Casting vs Coercion better than I did, and the working code above is as good as it gets. Hoping for some verification or refutation on both.

EDIT: Actually, that only works because my decimal is not .0. If I want to flag 3.0 as an error as well as 3.3 I really need to check for the decimal instead, like so.

if (($item -as [Int] -isnot [Int]) -or ($item -like '*.*')) {