# External ID query **URL:** \ **Category:** IBDMDB\ **Created:** [November 23, 2020, 10:18pm UTC](https://forum.biobakery.org/t/external-id-query/1329 "2020-11-23T22:18:29Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![paddy](https://avatars.discourse-cdn.com/v4/letter/p/77aa72/32.png) [@paddy](https://forum.biobakery.org/u/paddy)\ **Post date:** [November 23, 2020, 10:18pm UTC](https://forum.biobakery.org/t/external-id-query/1329/1 "2020-11-23T22:18:29Z")
Dear colleagues I have a quick query about the External ID column in the metadata file of the HMP2 project. There are some IDs which have endings with \_P. For example, CSM5FZ3N\_P - however CSM5FZ3N is also present. Are these completely different and independent samples ? Can you please clarify ? Looking forward to your kind response. Best regards Paddy ---
**Author:** ![sagunmaharjann](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.biobakery.org/sagunmaharjann/32/168_2.png) [@sagunmaharjann](https://forum.biobakery.org/u/sagunmaharjann)\ **Post date:** [April 20, 2021, 4:18pm UTC](https://forum.biobakery.org/t/external-id-query/1329/2 "2021-04-20T16:18:50Z")
Hi user, “\_P” indicates that the samples are Paired-End samples. Therefore the other sample should be just the merged/single-end. Since the sample\_id is the same, they are the same samples. Regards, Sagun ---
**Author:** ![hilasha2](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.biobakery.org/hilasha2/32/947_2.png) [@hilasha2](https://forum.biobakery.org/u/hilasha2)\ **Post date:** [May 30, 2023, 12:28pm UTC](https://forum.biobakery.org/t/external-id-query/1329/3 "2023-05-30T12:28:42Z")
Doesn’t ‘\_P’ simply indicate pilot? [https://ibdmdb.org/tunnel/public/summary.html](https://ibdmdb.org/tunnel/public/summary.html) ![image](https://canada1.discourse-cdn.com/flex027/uploads/biobakery/original/2X/0/0e6dffe742212a6f2c9c3a60db04a1c0e4fcb323.png) Each raw metagenome sample had two files, one ending with \_R1 the other with \_R2, whether they were named with ‘\_P’ or not.