Balido pa rin ang sertipikong medikal.

Because Filipino often uses a predicate-first sentence pattern.

In this sentence:

• Balido pa rin = the predicate part
• ang sertipikong medikal = the topic marked by ang

So the structure is closer to:

• Still valid
  • the medical certificate

A very literal English-like rearrangement would be something like Still valid is the medical certificate, although normal English says The medical certificate is still valid.

It is not stated, because Filipino often does not need a separate verb like is/are in simple descriptive sentences.

So:

• Balido pa rin ang sertipikong medikal.

naturally means:

• The medical certificate is still valid.

This kind of sentence is very common in Filipino. The idea of is is understood from the structure.

Pa rin means still.

It shows that the situation continues to be true. In this sentence, it means the medical certificate continues to be valid.

A useful way to learn it is to treat pa rin as a very common expression meaning:

• still
• continuing to be so

You will see it in many sentences, such as:

• Bukas pa rin. = It is still open.
• Maulan pa rin. = It is still raining.

Rin and din are variants of the same word.

A common rule is:

• use rin after a word ending in a vowel or the sounds w and y
• use din after most consonants

Since balido ends in a vowel, rin is the expected form:

• balido pa rin

In casual speech, people do sometimes mix them, but this version follows the standard pattern.

Ang marks the topic of the sentence.

Here, ang sertipikong medikal is the thing being talked about.

It is tempting to translate ang as the, but that is not always accurate. It is better to think of ang as a marker rather than a direct equivalent of the English article the.

So in this sentence:

• ang sertipikong medikal = the medical certificate in context

But grammatically, ang is doing more than just acting like the.

Because Filipino uses a linker between words that modify each other.

Here:

• sertipiko = certificate
• medikal = medical

To connect them, sertipiko takes the linker -ng:

• sertipiko + -ng + medikal → sertipikong medikal

This is a very common pattern when the first word ends in a vowel.

Compare:

• batang maliit = small child
• babaeng mabait = kind woman
• sertipikong medikal = medical certificate

Yes. That is also grammatical.

Both of these can mean medical certificate:

• sertipikong medikal
• medikal na sertipiko

The difference is mainly in word order and style. Filipino allows both noun + adjective and adjective + noun patterns, though some expressions may sound more natural or more formal in one order than the other depending on usage.

In official or formal phrasing, sertipikong medikal sounds very natural.

Balido is a borrowed word, ultimately from Spanish, and it is used in Filipino to mean valid.

This is very normal. Filipino contains many borrowed words, especially in formal, legal, medical, and administrative language.

So balido is perfectly acceptable and natural, especially in official contexts such as documents, permits, and certificates.

Yes, you may hear that, and it can also mean The medical certificate is still valid.

However:

• pa already gives a sense of still/yet
• pa rin makes the idea of still continuing more explicit

So balido pa rin sounds very clear and natural if you want to emphasize that it remains valid.

It sounds somewhat formal because of the vocabulary:

• balido
• sertipikong medikal

This is the kind of sentence you might see or hear in:

• offices
• clinics
• schools
• HR departments
• official announcements

In casual conversation, speakers might sometimes switch to more English-mixed phrasing, depending on the situation. But this sentence is fully natural and appropriate, especially in formal Filipino.