Η γιατρός είπε ότι δεν φάνηκε τίποτα σοβαρό στο αίμα.

Γιατρός is one of those Greek nouns that can refer to either a man or a woman, and its form often stays the same. The gender is shown by the article:

• ο γιατρός = the male doctor
• η γιατρός = the female doctor

So in this sentence, η γιατρός tells you the doctor is a woman.

Είπε means said.

It is the 3rd person singular form of the verb λέω / λέγω (to say), in the simple past (aorist):

• είπα = I said
• είπες = you said
• είπε = he/she/it said

Here it matches η γιατρός, so:

• Η γιατρός είπε = The doctor said

Ότι here means that and introduces a subordinate clause:

• Η γιατρός είπε ότι... = The doctor said that...

In English, that is often optional:

• The doctor said that nothing serious showed up...
• The doctor said nothing serious showed up...

Greek also sometimes omits ότι, but using it is very common and clear.

Do not confuse this ότι with ό,τι (with a comma-like accent mark), which means whatever / anything that.

Δεν is the standard negation word used before verbs in Modern Greek. It means not.

So:

• δεν φάνηκε = did not appear / did not show up

Greek normally places δεν directly before the verb (or before a clitic + verb group).

Φάνηκε is the aorist form of φαίνομαι, which usually means to appear, to seem, or to show up / be visible.

In this sentence, it has the sense of:

• showed up
• appeared
• was seen

So δεν φάνηκε τίποτα σοβαρό means something like:

• nothing serious showed up
• nothing serious appeared
• nothing serious was seen

This is a very natural way to talk about test results in Greek.

Yes, from an English-speaking perspective it can look like a double negative, but in Greek this is normal.

Greek commonly uses negative concord, which means the negative word and the negative particle appear together:

• δεν είδα τίποτα = I didn’t see anything
  • literally closer to I didn’t see nothing, but that is not how it works grammatically in Greek

So here:

• δεν φάνηκε τίποτα σοβαρό = nothing serious showed up

This is standard Greek, not an error.

Because τίποτα behaves like a neuter word, so the adjective agrees with it in the neuter singular:

• τίποτα σοβαρό = nothing serious

That is why the adjective is σοβαρό.

Compare:

• κάτι καλό = something good
• τίποτα περίεργο = nothing strange
• κάτι σημαντικό = something important

Even though the meaning in English may feel abstract, Greek treats τίποτα grammatically as neuter.

Στο αίμα literally means in the blood.

It is made of:

• σε = in / at / to
• το = the

These combine into:

• στο = in the

So:

• στο αίμα = in the blood

In context, this usually means in the blood test / in the bloodwork / in the blood results, not literally blood sitting somewhere in a dramatic sense.

Because αίμα (blood) is a neuter noun in Greek.

Its article is το:

• το αίμα = the blood

That is why after σε + το, you get στο αίμα.

Greek often uses an impersonal/result-oriented style in medical contexts. Instead of saying something like:

• The blood was fine

it is very natural to say:

• Δεν φάνηκε τίποτα σοβαρό στο αίμα
• literally: Nothing serious appeared in the blood

This focuses on what the test showed. It sounds natural and idiomatic in Greek, especially for doctors, test results, and examinations.

Yes, but the meaning would shift.

• φάνηκε = appeared / showed up at a specific point or as a result
• φαινόταν = was appearing / seemed / looked like more as an ongoing impression

So:

• δεν φάνηκε τίποτα σοβαρό = nothing serious showed up
• δεν φαινόταν τίποτα σοβαρό = nothing serious seemed visible / there didn’t seem to be anything serious

In medical-test language, φάνηκε is very natural because it refers to what the results revealed.

The given sentence is very natural:

• Η γιατρός είπε ότι δεν φάνηκε τίποτα σοβαρό στο αίμα.

Greek word order is somewhat flexible, but changes can affect emphasis. For example:

• Η γιατρός είπε ότι στο αίμα δεν φάνηκε τίποτα σοβαρό.

This is also possible and puts a bit more focus on στο αίμα.

But the original version is probably the most neutral and natural for everyday use.