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About the Universal Data Collection (UDC) System

Doctor examining boy with mother watchingThe Universal Data Collection (UDC) system was developed by a committee made up of staff from CDC, the hemophilia treatment centers (HTCs), and a person with a bleeding disorder. These members were chosen through the national network of HTCs to broadly represent the community. The members of this committee have provided oversight for the UDC system. Together, they have decided what data will be collected and how they will be used.

The data collected are used to find out how many people with bleeding disorders have complications and how severely they are affected, to study how different treatments affect patient health, to monitor the safety of blood products used to control bleeding, to assess quality of life, and to determine health issues that need more research.

UDC collects data from people with hemophilia and other bleeding disorders of all ages to better understand issues across the lifespan.

The type of health information collected includes:

  • Diagnosis
  • Bleeding history
  • Use of treatment products
  • Ability to attend school or work
  • Overall activity level
  • Joint range of motion of the hips, knees, shoulders, elbows, and ankles
  • Blood samples to check iron level and check for viruses
  • Quality-of-life information

Joint Problems

Repeated bleeding into joints causes chronic joint disease which can lead to pain, decreased movement (range of motion), and a reduced quality of life. One of the goals of UDC is to monitor joint health over time. Studying this information helps us learn more about what makes a person more likely to have joint problems and helps us develop ways to prevent them.

For example, UDC data showed that people who are overweight are more likely to have decreased movement in their joints. Data have also shown that the rates of overweight and obesity among children and adolescents with hemophilia are similar to those among the general population, which are currently at epidemic levels. As a result, CDC recommends that people with hemophilia and other bleeding disorders exercise and maintain a healthy weight to protect their joints.

Read about CDC’s work to promote healthy weight »

Blood Safety

Another important aspect of UDC is ensuring that blood products used by people with hemophilia do not contain known viruses. Participants in UDC give a blood sample each year during their annual clinic visit. A portion of this sample is tested for certain viruses. This testing can be an early indicator if certain harmful viruses are being transmitted through blood products that are used to treat bleeding disorders. Today, blood products in the United States are considered safe from known viruses. However, continued testing through the UDC system can help to ensure safety—both for the hemophilia community and for others using blood products.

Learn more about blood safety »

Children Younger Than 2 Years of Age with Bleeding Disorders

Smiling baby boyData are collected as part of the UDC system on infants and toddlers younger than 2 years of age. This is important because the complications of bleeding disorders that affect these young children are often different than those that affect older children and adults. CDC is collecting information on issues related to early bleeding that can lead to complications such as long-term neurologic effects due to bleeding in the brain or the development of an inhibitor. In addition, understanding the complications that occur in newborns with bleeding disorders during delivery and after routine procedures performed soon after birth can aid in early diagnosis and appropriate treatment and follow-up care.

Women and Girls with Bleeding Disorders

Recently, the UDC system has begun collecting data on issues specific to females with bleeding disorders. This was important because over the last 15 years, the number of women and girls with bleeding disorders visiting HTCs for care has steadily increased. As females continue to seek care at HTCs, there is a need to learn more about the issues facing women and girls with bleeding disorders.

The goals of this effort are to:

  • Generally characterize women and girls with bleeding disorders who are enrolled in an HTC.
  • Characterize bleeding associated with events that occur only in women, such as menstrual periods, pregnancy, and childbirth.
  • Investigate the kinds of services women and girls receive at an HTC.
  • Characterize patterns of care for women and girls with bleeding disorders.

Currently, 19 HTCs are participating in the first phase of this new data collection effort. It is anticipated that this initiative will be expanded to all HTCs in the future.


Sophisticated computer systems are needed to process and manage the UDC data and blood samples. CDC developed a computerized system that processes, tracks, links, and stores UDC data.

This system includes:

  • Desktop data entry application
  • Electronic data import system
  • Web-based data entry tools
  • Unique data identifier system
  • Laboratory tracking system
  • Reporting system
  • Hemophilia treatment center directory

HTCs that participate in the UDC system initially reported data to CDC on paper forms. The paper forms were mailed to CDC and manually entered into the database. To improve efficiency, CDC developed a system that could receive UDC data that had been entered by HTC staff into an electronic patient database tool developed and adopted by the HTC network. Use of this system has reduced the amount of time between collection of data at the HTC and receipt of data at CDC. In addition, because the software performs most data validations before the data leaves the HTC, use of the software has resulted in fewer data validation errors and increased efficiency.

The laboratory tracking system takes the blood sample information and links it with the clinical data information from the patient data forms. Once the data are linked, the system provides the CDC laboratory with test orders required for each patient’s blood sample. The laboratory specialists can upload test results directly into the database, and reports of patient results can be generated and transmitted to the HTC.

In addition, CDC needed a convenient and quick way to track and communicate with project staff at the HTCs. To meet this need, CDC created an online directory of HTC staff with the ability to send group e-mails.

Geographic Information Systems (GIS)

Where people live, work, and play can have a major effect on their health and well-being. CDC is using geographic information systems (GIS) to extend and strengthen the UDC system. GIS are a group of relatively new computer-based technologies that provide the ability to link, manage, and store geographic data from a variety of sources in one central virtual location. Increasingly, health professionals, advocates, and members of the hemophilia community are using maps and visual displays derived from UDC system data to inform and guide their activities.

For example, using GIS data we found that UDC system participants lived an average of 58 miles from their HTC and that about 20% lived more than 90 miles from their HTC. This information can be useful in planning outreach activities.

One HTC used the maps to create a treatment product exchange program with strategically located hospitals in the state. Through the program, unused factor product was rotated back to the HTC before the expiration date, ensuring that hospital pharmacies could maintain an up-to-date supply of factor products.

Mapping and other GIS technologies are powerful tools to use surveillance data in new and informative ways.

Laboratory Research

CDC’s hematologic research laboratories play a vital role in advancing the scientific knowledge of disorders such as hemophilia. We currently conduct studies to evaluate, improve, and standardize methods and procedures for classifying blood disorders. The laboratories conduct tests to identify exposures to bloodborne infections such as hepatitis and HIV, and they store samples for future investigations.

Future Research

Future studies are planned to learn more about:

  • The most common sites of bleeding that lead to a hemophilia diagnosis.
  • Diagnosis and bleeding symptoms among children with hemophilia who are younger than 2 years of age.
  • Links (if any) between the type of genes a person has and the likelihood the person will develop an inhibitor.
  • Joint disease and how it progresses among people who already have damaged joints.
  • Why some children with hemophilia have more loss of joint movement than others, even though they do not bleed more often.
  • Inhibitors (a substance in the body that stops or “inhibits” bleeding disorder treatments from working) and ways to find and measure them.
  • Hemophilia A and hemophilia B among women.
  • Bleeding in or around the brain.
  • Use of routine preventive treatment.
  • Use of devices that allow health care providers access to a patient’s vein to provide treatment or draw blood.
  • Causes of death among people with blood disorders.

Submit Research Proposals

The UDC Working Group is seeking proposals from investigators with research questions that may be addressed using data collected as part of UDC. Investigators from any discipline are encouraged to submit proposals using the following template and instructions.

UDC Research Proposal Submission Template [PDF ]

Accessing UDC Data

For information on how to access UDC data and how to submit a proposal for analysis, please see the “Organizational Structure and Guidelines.”


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