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Table of Contents: 2018 JANUARY–FEBRUARY No. 420

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New Maximum Length for Custom Filters in PubMed

Collins M. New Maximum Length for Custom Filters in PubMed. 2018 Jan-Feb;(420):e4.

2018 February 12 [posted]

In April 2018, NLM will start limiting the length of PubMed custom filters to 4,000 characters, and asterisks (*) for truncation will no longer be allowed in these filters. We are introducing a limitation on this My NCBI feature to address resource-intensive demands on the system and to continue providing a rapid response time for all PubMed users.

Custom filters appear on the right sidebar menu and are configured in My NCBI (see Figure 1).


Custom filters created and managed in My NCBI appear on the right sidebar menu.
Figure 1: Custom filters created and managed in My NCBI appear on the right sidebar menu.

If you use custom filters in PubMed that contain more than 4,000 characters and/or an asterisk (*) for truncation, you can prepare for this change now by updating your custom filters. For any searches that are affected by this change, click on the gear icon (see Figure 2) and edit the search so that it contains fewer than 4,000 characters and no asterisks.


Click on the gear icon to edit your search terms.
Figure 2: Click on the gear icon to edit your search terms.

After the new rules are implemented, custom filters that exceed 4,000 characters and/or include an asterisk (*) will be disabled. In this example, the filter named "Heart" contains more than 4,000 characters and/or an asterisk (*) for truncation. Under the new rules for custom filters, the filter "Heart" is deselected on this page and no longer appears on the results page in PubMed. Custom filters that do not exceed 4,000 characters or include any asterisks (*) are not affected. In the example above, the custom filters "Animals" and "Pathology Journals are not affected and remain active on the results page in PubMed. Standard filters are not affected.

You can also create a saved search with the entire search from the affected filter (see Figure 3).

  1. Click on the gear icon to edit the search.
  2. In the "Edit Custom Filter in PubMed" popup window, right-click on the Query terms to select and copy the search.
  3. Click on "X" to close this popup window.

    Copy your search terms to create a My NCBI saved search.
    Figure 3: Copy your search terms to create a My NCBI saved search.
  4. Return to PubMed and paste the query terms into the search box to run the search.
  5. Click on "Create alert" under the search box.
  6. On the next screen, you can edit the saved search (see Figure 4). For more information, please see "Saving and Managing Searches" in PubMed help.

    Configure your saved search. Figure 4: Configure your saved search.

To use this saved search in place of a filter:

  1. Go to My NCBI and click on the Saved Search to run it. This will give you the results of the search – which is equivalent to the filter.

    Click on the PubMed Search to see the results.
    Figure 5: Click on the PubMed Search to see the results.
  2. Use the Advanced Search Builder (see Figure 6) to combine these results with any search. For more information, please see "Advanced Search" in PubMed help.

    PubMed Advanced Search Builder.
    Figure 6: PubMed Advanced Search Builder.

By Marie Collins
National Center for Biotechnology Information

NLM Technical Bulletin National Library of Medicine National Institutes of Health