Η εξέταση αίματος δείχνει ότι δεν υπάρχει σοβαρό πρόβλημα.

Η is the feminine singular definite article, meaning the.

So η εξέταση = the test / the examination.

Greek uses the definite article very often, just like English does. Since the sentence refers to a specific test, Greek naturally says η εξέταση.

Also, εξέταση is a feminine noun, so it takes η in the nominative singular.

Because αίματος is in the genitive case.

In Greek, the genitive is often used to show a relationship like of in English. So:

• εξέταση = test
• αίματος = of blood

So εξέταση αίματος literally means test of blood, which is the normal Greek way to say blood test.

This is very common in Greek:

• ποτήρι νερού = glass of water
• πόρτα σπιτιού = door of a house / house door
• ανάλυση αίματος = blood analysis

Αίμα is a neuter noun. Its basic dictionary form is το αίμα.

Here are the relevant singular forms:

• το αίμα = the blood (nominative / accusative)
• του αίματος = of the blood (genitive)

In εξέταση αίματος, the article του is omitted, which is very normal in this kind of noun phrase. So the phrase uses just the genitive noun:

• αίματος = of blood

That is why you see αίματος, not αίμα.

Because the subject is η εξέταση αίματος, which is singular.

The verb δείχνει means shows and is the third person singular form of δείχνω.

So the structure is:

• Η εξέταση αίματος = the blood test
• δείχνει = shows

If the subject were plural, the verb would also be plural:

• Οι εξετάσεις αίματος δείχνουν... = The blood tests show...

Ότι means that and introduces a subordinate clause.

So:

• Η εξέταση αίματος δείχνει = The blood test shows
• ότι δεν υπάρχει σοβαρό πρόβλημα = that there is no serious problem

This is very similar to English.

A useful thing to know: ότι can also be written as πως in many contexts, especially in everyday Greek:

• δείχνει ότι...
• δείχνει πως...

Both can mean shows that...

In Greek, δεν is the standard negation word used before most finite verbs.

So:

• υπάρχει = there is / exists
• δεν υπάρχει = there is not / there isn’t

This is the normal position. The negative particle goes directly before the verb.

Compare:

• υπάρχει πρόβλημα = there is a problem
• δεν υπάρχει πρόβλημα = there is no problem

Because υπάρχει means exists / there is, which is the natural choice for saying whether something is present or not.

So:

• δεν υπάρχει σοβαρό πρόβλημα = there is no serious problem

If you used είναι, the meaning would change. Είναι means is and usually links a subject to a description:

• Το πρόβλημα είναι σοβαρό. = The problem is serious.

But here the idea is not the problem is serious. The idea is there is no serious problem. That is why υπάρχει is the right verb.

Because πρόβλημα is a neuter noun, and the adjective must agree with it in gender, number, and case.

So:

• σοβαρός = masculine
• σοβαρή = feminine
• σοβαρό = neuter

Since πρόβλημα is neuter singular, the adjective must also be neuter singular:

• σοβαρό πρόβλημα = serious problem

This kind of agreement is a very important feature of Greek grammar.

Because Greek often omits the indefinite article in cases like this, especially after υπάρχει / δεν υπάρχει.

So:

• δεν υπάρχει σοβαρό πρόβλημα = there is no serious problem

You could sometimes also hear:

• δεν υπάρχει ένα σοβαρό πρόβλημα

but that usually sounds different in meaning or emphasis and is not the natural neutral choice here.

Greek does have an indefinite article, based on ένας / μία / ένα, but it is used less automatically than English a/an. In existential sentences like this, a bare noun phrase is very common.

The singular is the most natural choice because the sentence is talking generally about the absence of any serious issue.

• δεν υπάρχει σοβαρό πρόβλημα = there is no serious problem

Greek could use a plural in a different context:

• δεν υπάρχουν σοβαρά προβλήματα = there are no serious problems

That would shift the meaning slightly toward multiple problems. The singular here sounds more like a general medical conclusion.

Greek word order is more flexible than English, but this sentence is already in a very natural and neutral order.

Standard order:

• Η εξέταση αίματος δείχνει ότι δεν υπάρχει σοβαρό πρόβλημα.

You can change word order for emphasis, but not every change sounds equally natural. For example:

• Η εξέταση αίματος δείχνει ότι σοβαρό πρόβλημα δεν υπάρχει.

This is possible, but more marked and emphatic, almost like as for a serious problem, there isn’t one.

For learners, the original order is the best pattern to remember.

A simple pronunciation guide is:

i exétasi ématos díchni óti den ipárchi sovaró próvlima

A few helpful notes:

• η sounds like ee
• αι usually sounds like e
• χ in υπάρχει is a rough sound, like the h-like sound in German Bach or Scottish loch
• Stress matters in Greek, so pay attention to the accented syllables:
  • εξέταση
  • αίματος
  • δείχνει
  • ότι
  • υπάρχει
  • σοβαρό
  • πρόβλημα

If you ignore stress, your Greek may still be understandable, but it will sound much less natural.

Usually, no.

In Greek, a comma before ότι is generally not required in a sentence like this:

• Η εξέταση αίματος δείχνει ότι δεν υπάρχει σοβαρό πρόβλημα.

This differs a bit from some English punctuation habits. Greek punctuation tends to avoid a comma before a straightforward that-clause unless there is some special reason.

So the sentence as written is correctly punctuated.

It is neutral and standard Greek. It sounds exactly like something you might read in a medical report or hear from a doctor.

A more casual spoken version might be something like:

• Η εξέταση αίματος δείχνει πως δεν υπάρχει σοβαρό πρόβλημα.

That is only a small difference. The original sentence is completely natural and standard.