El médico revisó la sangre.

A simple English-style approximation is:

el ME-di-ko re-bi-SO la SAN-gre

A few useful notes:

• médico is stressed on ME
• revisó is stressed on the last syllable, SO
• the c in médico is a hard k sound
• in Spain, the r in sangre is a tapped r, not an English r

The written accents in médico and revisó show where the stress goes.

The accent marks show irregular stress.

• médico would normally be stressed differently without the accent, so the accent tells you to stress ME
• revisó has an accent to show that the stress is on the last syllable: re-vi-SÓ

In Spanish, accent marks are not optional. They are part of the correct spelling.

Because el médico means the doctor.

In Spanish, you usually need an article like el, la, un, or una before a noun when you are talking about a specific person or thing.

So:

• El médico = the doctor
• Un médico = a doctor

You can say just médico in some special structures, such as after ser:

• Es médico = He/She is a doctor

But as the subject of this sentence, el médico is the normal form.

Yes. El médico normally refers to a male doctor.

If you mean a female doctor, in standard modern Spanish you would usually say:

• La médica

So:

• El médico revisó la sangre = the male doctor checked the blood
• La médica revisó la sangre = the female doctor checked the blood

In some contexts, the masculine form can be used more generally, but here el médico naturally sounds male.

It comes from revisar, but in Spanish revisar usually means to check, to inspect, to examine, or to review.

So in this sentence, revisó la sangre means something like:

• checked the blood
• examined the blood
• reviewed the blood sample/results

This is a common false-friend area for English speakers. Spanish revisar often does not mean revise in the English sense of rewriting or editing.

It is the preterite tense, third person singular.

That means:

• revisó = he checked, she checked, or it checked

The infinitive is revisar. Its preterite forms include:

• revisé = I checked
• revisaste = you checked
• revisó = he/she checked
• revisamos = we checked
• revisasteis = you all checked
• revisaron = they checked

Here, because the subject is El médico, revisó means the doctor checked/examined.

Because Spanish often leaves out subject pronouns when they are not needed.

The verb ending already tells you the subject is he/she/it in the preterite:

• revisó = he/she checked

And the noun El médico already tells you who did the action. So adding él would usually be unnecessary:

• El médico revisó la sangre = normal
• Él revisó la sangre = possible, but only if you want emphasis or contrast

This is called a pro-drop language feature.

Spanish often uses the definite article more than English does.

Here, la sangre means the blood. It can refer to a specific blood sample, or simply to the blood being examined in the situation.

English sometimes prefers no article in places where Spanish uses one. Spanish is more comfortable saying la sangre, especially when referring to something concrete in context.

Also, sangre is a feminine noun, so it takes la:

• la sangre

Because grammatical gender in Spanish is a property of the noun itself, and sangre is feminine.

So you say:

• la sangre
• mucha sangre
• sangre roja

There is not always a logical reason that matches biological sex. Blood is not female; sangre is simply a feminine noun grammatically.

Because the personal a is mainly used before specific human direct objects, and sometimes pets or personified beings.

Examples:

• Veo al médico = I see the doctor
• Veo a María = I see María

But la sangre is not a person, so no personal a is used:

• El médico revisó la sangre

That is completely normal.

Yes. This is a very standard subject + verb + object sentence:

• El médico = subject
• revisó = verb
• la sangre = direct object

Spanish can change word order for emphasis, style, or context, but this version is the most neutral and straightforward.

Yes. Doctor and médico can both refer to a doctor.

In Spain, médico often sounds a bit more directly like physician/medical doctor, while doctor is also very common in everyday speech.

So both are possible:

• El médico revisó la sangre
• El doctor revisó la sangre

The sentence with médico is perfectly natural.

Not necessarily.

Revisó la sangre most naturally means the doctor checked or examined the blood, or possibly reviewed blood results. It does not by itself guarantee a full laboratory analysis.

If you specifically want analysed the blood, Spanish might use:

• analizó la sangre

So revisó is a bit broader and can mean looked over / checked / examined in a medical context.