A service of the U.S. National Library of Medicine 
National Institutes of Health
MedlinePlus Connect: Web Service
MedlinePlus Connect is available as a Web application or Web service. Below are the technical details for implementing the Web service, which responds to requests based on diagnosis (problem) codes, medication codes, and lab tests. If you use data from the MedlinePlus Connect Web Service, please indicate that the information is from MedlinePlus.gov.
The REST-based MedlinePlus Connect Web service conforms to the HL7 Context-Aware Knowledge Retrieval (Infobutton) Service-Oriented Architecture Implementation Guide, January 2011 Draft, which uses Atom as the framework for the knowledge response. The output of the request is XML, which is presented in the Atom feed format.
The structure of the request indicates what type of code you are sending. In all cases, the base URL for the Web service is:
MedlinePlus Connect works over HTTP or HTTPS.
If you decide to use MedlinePlus Connect, sign up for the email list to keep up with developments and exchange ideas with your colleagues. Please tell us if you implement MedlinePlus Connect by contacting us.
Requests for Diagnosis (Problem) Codes
For a problem code, MedlinePlus Connect will return links and information for up to three MedlinePlus health topic pages. The service can provide a response to a diagnosis code request in English or Spanish.
MedlinePlus Connect will return the following:
- MedlinePlus health topic page title (up to three matches). To see the range of possible matches, refer to the full list of MedlinePlus health topics.
- MedlinePlus health topic page URL
- Synonyms for that topic ("Also called")
- MedlinePlus health topic summary, including formatting and links to other appropriate MedlinePlus topics
- Summary attribution
- Selected links for patients, including formatting, the page name, URL, and associated organization (when applicable)
The base URL of the service is:
There are two required parameters for any query to this service:
- Code System
- Identify the problem code system you will be using, either ICD-9-CM or SNOMED CT. Note: MedlinePlus Connect coverage of SNOMED CT focuses on the CORE Problem List subset codes and their descendants.
- For ICD-9-CM use:
- mainSearchCriteria.v.cs=2.16.840.1.113883.6.103
- MedlinePlus Connect will also accept:
- mainSearchCriteria.v.cs=2.16.840.1.113883.6.2
- mainSearchCriteria.v.cs=2.16.840.1.113883.6.42
- For SNOMED CT use:
- mainSearchCriteria.v.cs=2.16.840.1.113883.6.96
- Code
- Identify the actual code that you are trying to look up:
- mainSearchCriteria.v.c=250.33
Optional Parameters
Code TitleYou may also identify the name/title of the problem code. However, this information does not impact the response (unlike the MedlinePlus Connect Web application where the name/title information may be used).
Language
Identify if you would like the request to be in English or Spanish. MedlinePlus Connect will assume English is the language if it is not specified.
If you wish the response to the problem code lookup to be in Spanish, use:
To specify English, use the following:
Description of Selected Atom: Entry Node Elements in Response to Problem Code Requests
| Element | Class node | Description |
|---|---|---|
| title | Title of matched MedlinePlus health topic page | |
| URL | URL for matched MedlinePlus health topic page | |
| summary | The full summary for the health topic. This includes embedded links to other relevant health topics, and all formatting, including bullets and paragraph spacing. The summary is in HTML. | |
| summary | class="NLMalsoCalled" | Synonyms for the topic. These are referred to as "Also called" on a health topic page. Not all topics have "Also called" terms. |
| summary | class="NLMattribution" | Attribution acknowledgement for summary text, if the majority of the summary was from another federal agency. Not all summaries have an attribution. Unattributed text is original to MedlinePlus. |
| summary | class="NLMrelatedLinks" | Selected links associated with the topic. This includes the page name, URL, and associated organization (when applicable). The links are formatted in a bulleted list. Not all topics have these links. The number of links can range from zero to dozens. |
Examples of Requests for Problem Codes
A complete request for Diabetes Mellitus with other coma type 1 uncontrolled, ICD-9 code 250.33, for a Spanish speaking patient would have the following URL address:
A patient diagnosed with "Pneumonia due to Pseudomonas" using SNOMED CT code 41381004:
Related Services and Files
To receive MedlinePlus health topics in response to text requests, as opposed to problem codes, investigate the MedlinePlus Web service. Also, if you need the full set of MedlinePlus health topics in XML format, see our XML files page.
Requests for Drug Information
MedlinePlus Connect provides the best drug information matches when receiving an RXCUI. It also provides good results when receiving an NDC code. If you do not send an NDC code, the system will use the text string that you send to display the best possible drug information match. There may not always be a match for each request. In those cases, MedlinePlus Connect will return a null response.
The MedlinePlus Connect Web service returns a link to a search results page with the best matches from the MedlinePlus drug information. MedlinePlus Connect does not return direct links to individual MedlinePlus drug information pages because of NLM's agreement with the MedlinePlus medication content provider.
At this time, MedlinePlus Connect provides responses to medication information in English only.For requests for drug information, the base URL is:
To send a request, include these pieces of information:
- Code System Identify the type of medication code you are sending.
- mainSearchCriteria.v.cs=2.16.840.1.113883.6.88
- mainSearchCriteria.v.cs=2.16.840.1.113883.6.69
- Code Identify the actual code you are trying to look up.
- mainSearchCriteria.v.c=637188
- Drug Name Identify the name of the drug with a text string.
- mainSearchCriteria.v.dn=Chantix 0.5 MG Oral Tablet
For RXCUI use:
For NDC use:
MedlinePlus Connect can also accept a text string, but you must indicate you are looking for medication information by including one of the two code systems listed above.
Description of Selected Atom: Entry Node Elements in Response to Medication Requests
| Element | Description |
|---|---|
| title | General title "Results from MedlinePlus Connect" |
| URL | URL for the MedlinePlus Connect response page that includes link(s) to matching MedlinePlus drug information. |
Your medication information request should look like one of the following.
To request information by an RXCUI, your request should look like this:
To request information by an NDC, your request should look like this:
To send a Text String without a medication code, you must identify your query as an NDC-type request so MedlinePlus Connect knows you are looking for medication information. Your request could look like this:
Requests for Lab Test Information
MedlinePlus Connect provides matches to laboratory test information when receiving a LOINC request. The service can provide a response in English or Spanish.
The MedlinePlus Connect Web service will return the following:
- MedlinePlus lab test page title
- MedlinePlus lab test page URL
The base URL of the service is:
These are two required parameters for any lab test query to this service:
- Code System
- Identify that you are using the LOINC code system. Use:
- mainSearchCriteria.v.cs=2.16.840.1.113883.6.1
- MedlinePlus Connect will also accept:
- mainSearchCriteria.v.cs=2.16.840.1.113883.11.79
- Code
- identify the actual code you are trying to look up:
- mainSearchCriteria.v.c=3187-2
Optional Parameters
Code TitleYou may also identify the name of the lab test. However, this information does not impact the response.
Language
Identify if you would like the request to be in English or Spanish. MedlinePlus Connect will assume English is the language if it is not specified.
If you wish the response to be in Spanish, use:
To specify English, use:
Description of Selected Atom: Entry Node Elements in Response to Lab Test Requests
| Element | Description |
|---|---|
| title | Title of matched MedlinePlus lab test page |
| URL | URL for matched MedlinePlus lab test page |
Examples of Requests for Lab Tests
To request information for an English speaker, your request may look like one of the following:
http://apps.nlm.nih.gov/medlineplus/services/mpconnect_service.cfm?mainSearchCriteria.v.cs=2.16.840.1.113883.6.1&mainSearchCriteria.v.c=3187-2&mainSearchCriteria.v.dn=Factor%20IX%20assay&informationRecipient.languageCode.c=en
http://apps.nlm.nih.gov/medlineplus/services/mpconnect_service.cfm?mainSearchCriteria.v.cs=2.16.840.1.113883.6.1&mainSearchCriteria.v.c=3187-2&informationRecipient.languageCode.c=en
To request information for a Spanish speaker, your request may look like one of the following:
http://apps.nlm.nih.gov/medlineplus/services/mpconnect_service.cfm?mainSearchCriteria.v.cs=2.16.840.1.113883.6.1&mainSearchCriteria.v.c=3187-2&mainSearchCriteria.v.dn=Factor%20IX%20assay&informationRecipient.languageCode.c=sp
http://apps.nlm.nih.gov/medlineplus/services/mpconnect_service.cfm?mainSearchCriteria.v.cs=2.16.840.1.113883.6.1&mainSearchCriteria.v.c=3187-2&informationRecipient.languageCode.c=sp
More Information
- MedlinePlus Connect overview
- Web application demonstration
- Web service demonstration
- MedlinePlus Connect email list
- Technical information for developers