Ako pretraga bude gotova danas, pacijentica će dobiti dijagnozu odmah.

Because after ako when you are talking about a future condition, Croatian normally does not use future I in the if-clause.

So Croatian says:

• Ako pretraga bude gotova danas...
• not normally Ako pretraga će biti gotova danas...

Here bude gotova is the normal way to express something like if the examination is finished / has been completed by that future time.

This is a very common pattern in Croatian:

• Ako budeš imao vremena, nazovi me. = If you have time, call me.
• Ako vlak stigne na vrijeme, krenut ćemo odmah. = If the train arrives on time, we’ll leave immediately.

So the main idea is:

• subordinate future condition after ako -> bude / present-like form
• main clause -> often će + infinitive

Gotova is not the main verb here. It is an adjective meaning finished, ready, or completed.

The verb is bude from biti (to be), and gotova describes the state of pretraga.

So the structure is:

• pretraga = the examination / scan / test
• bude = is / will be
• gotova = finished

Literally, it is close to:

• If the examination is finished today...

Because gotova is an adjective, it has to agree with the noun it describes.

Because gotova agrees with pretraga, and pretraga is:

• feminine
• singular
• nominative

So the adjective must also be feminine singular nominative:

• gotov = masculine
• gotova = feminine
• gotovo = neuter

Examples:

• pregled je gotov = the examination is finished
  (pregled is masculine)
• pretraga je gotova = the scan/test is finished
  (pretraga is feminine)

Because dijagnozu is the direct object of dobiti (to receive / get), so it must be in the accusative case.

The noun changes like this:

• dijagnoza = nominative singular
• dijagnozu = accusative singular

This is a very common pattern for feminine nouns ending in -a:

• knjiga -> knjigu
• poruka -> poruku
• dijagnoza -> dijagnozu

So:

• pacijentica = subject
• će dobiti = will receive
• dijagnozu = object

Because dobiti is perfective, and it fits a single completed event: receiving the diagnosis one time.

• dobiti = to get / receive once, as a completed action
• dobivati = to be getting / to get repeatedly / habitually

In this sentence, the patient will receive the diagnosis at one specific moment, so dobiti is the natural choice.

Compare:

• Pacijentica će dobiti dijagnozu odmah.
  = The patient will receive the diagnosis immediately.

• Pacijentica je često dobivala različite upute.
  = The patient was often receiving / getting different instructions.

So this is mainly a question of aspect:

• perfective for one completed event
• imperfective for repeated, ongoing, or habitual action

Because Croatian has no articles.

English says:

• the examination
• a diagnosis
• the patient

Croatian usually just says:

• pretraga
• dijagnoza / dijagnozu
• pacijentica

Whether something means a or the is usually understood from context.

So pacijentica će dobiti dijagnozu odmah can mean:

• the patient will get the diagnosis immediately
• or, depending on context, a patient will get a diagnosis immediately

In real use, context tells you which one is meant.

Yes. Croatian word order is much more flexible than English word order because case endings help show what each word is doing.

The sentence you have is natural and neutral:

• Ako pretraga bude gotova danas, pacijentica će dobiti dijagnozu odmah.

But you could also say:

• Ako pretraga bude gotova danas, pacijentica će odmah dobiti dijagnozu.
• Ako danas pretraga bude gotova, pacijentica će dobiti dijagnozu odmah.

These versions are all understandable. The difference is mostly one of focus or style, not basic meaning.

A useful rule:

• the version in your sentence is a good neutral default
• moving words like danas or odmah changes emphasis

Ako means if, so it presents the finishing of the examination as a condition.

• Ako pretraga bude gotova danas...
  = If the examination is finished today...

This suggests that it may or may not happen.

If you used kad, the meaning would be closer to when, and it would sound more expected or assumed:

• Kad pretraga bude gotova danas, pacijentica će dobiti dijagnozu odmah.

That sounds more like the speaker expects the examination to be finished, and then the diagnosis will follow.

So:

• ako = conditional, not certain
• kad = when, more expected/assumed

Because pacijentica is the feminine form and means female patient.

• pacijent = male patient, or sometimes patient in a more general/default sense
• pacijentica = female patient

Croatian often marks natural gender in nouns for people.

Examples:

• student / studentica
• profesor / profesorica
• pacijent / pacijentica

So this sentence specifically refers to a woman or girl who is the patient.

Pretraga is in the nominative singular because it is the subject of the clause Ako pretraga bude gotova danas.

It is the thing that becomes finished.

So the first clause breaks down like this:

• Ako = if
• pretraga = the examination / scan / test
• bude gotova = is finished / has been completed
• danas = today

Its role is different from dijagnozu, which is the object in the second clause.

So the sentence has:

• one subject in the first clause: pretraga
• another subject in the second clause: pacijentica
• one object in the second clause: dijagnozu