byouin de ketueki wo sirabeta.

で marks the place where an action happens.

So 病院で means at the hospital or in the hospital, in the sense that the action of examining/testing happened there.

A useful comparison:

• 病院で調べた = examined/tested something at the hospital
• 病院に行った = went to the hospital

So here, で is not marking destination. It marks the location of the action.

を marks the direct object of the verb, meaning the thing that is being acted on.

In this sentence:

• 血液 = blood
• 血液を = blood, as the thing being examined/tested

The verb 調べた acts on 血液, so を is used.

A very literal breakdown would be:

• 病院で = at the hospital
• 血液を = blood
• 調べた = examined / tested

調べた is the plain past tense of 調べる.

• Dictionary form: 調べる = to examine, to investigate, to check, to test
• Plain past: 調べた = examined / tested / checked
• Polite past: 調べました

So this sentence is in a casual/plain style, not the polite ます style.

Japanese often omits the subject when it is clear from context or not important.

So 病院で血液を調べた。 could mean things like:

• I had my blood tested at the hospital
• They tested blood at the hospital
• The doctor examined the blood at the hospital

The exact subject is not stated in the sentence itself. You figure it out from context.

This is very normal in Japanese.

Grammatically, it literally means examined/tested blood.

But in real context, English often expresses this more naturally as something like:

• had a blood test
• got my blood tested
• had my blood examined

Japanese does not always state possession as explicitly as English does. So even though the sentence says blood, the real-world meaning may be my blood, a patient's blood, or a blood sample, depending on context.

Yes, 血液 is natural, especially in a medical context.

• 血 means blood, but it can sound more basic, direct, or less technical
• 血液 is a more formal/scientific word for blood

In a hospital or testing context, 血液 sounds very appropriate.

Also, in real life, Japanese often uses expressions like:

• 血液検査をした = did a blood test
• 血を調べた = examined the blood

So 血液を調べた is understandable and natural, especially in a medical setting.

Japanese is basically an SOV language: subject-object-verb.
The verb normally comes at the end of the sentence.

So:

• 病院で = at the hospital
• 血液を = blood
• 調べた = examined/tested

The final verb tells you what happened to everything that came before it.

This is one of the biggest differences from English, where the verb usually comes earlier.

Yes, Japanese word order is fairly flexible because particles show each word’s role.

For example, these are all possible:

• 病院で血液を調べた。
• 血液を病院で調べた。

Both can mean essentially the same thing.

However, the original order is very natural. Changing the order may shift emphasis slightly:

• 病院で血液を調べた。 = neutral/basic order
• 血液を病院で調べた。 = puts a bit more focus on blood

Even though order can change, the verb usually still stays at the end.

Yes. 調べる has a broad meaning: to examine, check, investigate, look into, test.

The best English translation depends on context.

With 血液, the most natural English choices are usually:

• tested
• examined
• checked

So in this sentence, tested the blood or examined the blood is more natural than investigated the blood.

Yes. The polite version would be:

病院で血液を調べました。

The only change is:

• 調べた → 調べました

This makes the sentence polite, but the basic meaning stays the same.

So:

• 病院で血液を調べた。 = plain/casual
• 病院で血液を調べました。 = polite

By itself, it does not fully specify that.

Japanese often leaves that kind of information unstated if context makes it clear.

So depending on context, it could mean:

• I had my blood tested at the hospital
• We tested the blood at the hospital
• The doctor examined the blood at the hospital

If you wanted to make it clearer, Japanese would need extra words. But as it stands, the sentence simply states that the action of examining/testing blood happened at a hospital.