The study is being conducted to determine if the blood test Brain Natriuretic Protein (BNP) can demonstrate the presence of extra fluid in patients with chronic kidney disease treated by hemodialysis. It will also try to determine the blood test Procalcitonin (PCT) can help identify the cause of the fever, specifically if a fever is caused by a bacterial infection. It will also evaluate whether new blood tests in the future (such as DNA, RNA, metabolite, and protein based tests) can be developed to help predict other complications in patients with chronic kidney disease treated by hemodialysis.

The study has three purposes:

1. To establish a procalcitonin (PCT) algorithm to assist in the identification of bacterial infection in patients with fever and chronic kidney disease (CKD) being treated by hemodialysis;
2. To establish an algorithm to assist clinicians in distinguishing infection from fluid overload in patients with CKD treated by hemodialysis with shortness of breath using PCT and brain natriuretic peptide (BNP);
3. To allow for evaluation of new tests, such as DNA, RNA, metabolite, and protein based tests, which might prove useful in the evaluation of clinical complications encountered by patients with chronic kidney disease treated by hemodialysis including infections and fluid overload.

Baseline Visit:

1. Review of medical and medication history
2. A physical exam and routine clinical laboratory tests (hematology and chemistry) will be performed.
3. PCT and BNP levels will be measured twice prior to hemodialysis (HD) treatment to establish baseline levels.
4. Optional: If the subject consent, samples will be obtained for genetic tests (DNA, RNA, metabolite and proteins) for new tests to be developed in the future.

Follow Up:

1. A physical exam, routine clinical laboratory tests (hematology and chemistry) and medical and medication review will be obtained monthly.

If a subject develops signs of infection or shortness of breath during the course of the study, additional research blood samples for procalcitonin, brain natriuretic peptide, and for genetic testing (Optional) will be obtained as follows:

1. For patients with suspected infection, PCT levels will be drawn at the time of suspected infection and again at the start of the next HD treatment.
2. For patients with shortness of breath, PCT and BNP levels will be drawn at the time of the complaint and again at the start of the next HD treatment.

Inclusion Criteria:

1. Males and females, 18 years and older.
2. Subject is receiving hemodialysis.
3. Able to provide informed consent.

Exclusion Criteria:

1. Subject is unable or unwilling to provide informed consent.

Potential subjects are those who are receiving hemodialysis at The Rogosin Institute.