Parse PHP array and store it’s value in associative array

Can anyone please help me how to parse this PHP array as It gives error in foreach loop and even It’s not working to get values using index.

$PatientTestArray = Array
(
    [0] => Array
        (
            [tube_number] => 230389414
            [test_group] => Fasting blood Sugar 
        )

    [1] => Array
        (
            [tube_number] => 230389418
            [test_group] => HbA1c 
        )

    [2] => Array
        (
            [tube_number] => 230388418
            [test_group] => HbA1c 
        )
)
print_r($PatientTestArray); //This works it print all the array
//This below code returns Null , it returns empty string.
foreach ($PatientTestArray as $key => $value) {
       echo $value;
       print_r($value);
}

The above array is fetched from mysql database and it looks like a string to me, I changed it’s type to array to parse it and also I tried different many solutions, can anyone know how can I parse below array.
I tried different solutions but nothing helps me to fix this.