A Comprehensive Guide to Your Laboratory Tests

If you’ve received a diagnosis of chronic kidney disease (CKD), comprehensive testing plays a crucial role in helping both you and your healthcare team gain insights into your body’s internal processes and the effectiveness of your treatment plan.

Your doctor will tailor specific tests based on the stage of kidney disease you’re currently in. Individuals in the early stages of kidney disease typically undergo tests that evaluate their kidney function, while those in advanced stages of kidney disease or receiving dialysis will have tests to assess the efficacy of their treatments. If you’re a patient with American Dialysis Centers, you have the convenience of accessing your lab results through the American Dialysis Centers Health Portal™ and sharing them with your kidney care team. Here’s an overview of some of the most common tests that your doctor may order:

Serum Creatinine

• Purpose: To ascertain the concentration of creatinine in your bloodstream.
• Normal Range: Typically falls within the range of 0.8 to 1.4 milligrams per deciliter (mg/dl).
• Test Procedure: A blood sample is collected and sent for thorough analysis.
• Test Frequency: Conducted throughout various stages of CKD, including end-stage renal disease (ESRD).

GFR—Glomerular Filtration Rate

• Purpose: To determine the extent of kidney function in an individual.
• Normal Range: Generally considered normal if it’s 90 or higher, with minimal or no presence of protein or albumin in urine.
• Test Procedure: This test involves a calculated value based on factors like your creatinine level, age, gender, and other relevant variables.
• Test Frequency: Applicable throughout all stages of CKD, including ESRD.

Changes to your GFR will tell your doctor how fast or slow your condition is progressing.

Microalbumin

• Purpose: Detects the presence of a protein called albumin in urine, which can indicate kidney damage.
• Normal Range: Virtually no albumin should be detected.
• Test Procedure: Involves collecting a urine sample from the individual being tested.
• Test Frequency: Typically performed in the early stages of CKD and annually for individuals with diabetes or hypertension.

BUN — Blood Urea Nitrogen

• Purpose: Detects elevated waste levels in the bloodstream, an early sign of reduced kidney function.
• Normal Range: Falls within 7 to 20 milligrams per deciliter (mg/dl).
• Test Procedure: Requires a blood sample, which is then sent for analysis.
• Test Frequency: Conducted during diagnosis, early and advanced stages of CKD, including end-stage renal disease (ESRD), to assess treatment effectiveness.

CCr — Creatinine Clearance

• Purpose: Measures how efficiently the kidneys filter creatinine and eliminate waste.
• Normal Range: For men, normal values range from 97 to 137 milliliters per minute, while for women, it’s typically 88 to 128 milliliters per minute.
• Test Procedure: Involves both blood and urine samples sent for analysis.
• Test Frequency: Performed when a person initiates dialysis or as part of a nutritional assessment.

Hb — Hemoglobin

• Purpose: Determines the hemoglobin levels in red blood cells and screens for anemia.
• Normal Range: In adults, the normal range is 12 to 18 grams per deciliter of blood.
• Test Procedure: Requires a blood sample, often conducted as part of a complete blood count (CBC) or complete blood test.
• Test Frequency: Throughout the early and later stages of CKD, including ESRD.

Hct — Hematocrit

• Purpose: Measures the percentage of red blood cells in the blood and screens for anemia.
• Normal Range: For adult females, the range is usually 36 to 47 percent, while for adult males, it’s 40 to 53 percent. For dialysis patients, the target hematocrit range is typically 33 to 36 percent.
• Test Procedure: Involves a blood sample, often conducted as part of a CBC or complete blood test.
• Test Frequency: Throughout the early and later stages of CKD, including ESRD.

URR — Urea Reduction Ratio

• Purpose: Measures the removal of urea during a hemodialysis session.
• Target Range: URR should be over 65 percent.
• Test Procedure: Involves taking a blood sample before and after a dialysis session.
• Test Frequency: Typically performed once every 12 to 14 dialysis sessions, approximately once a month.

Kt/V

• Purpose: Evaluates how effectively dialysis cleans your blood.
• Target Range (Hemodialysis Patients): More than 1.2.
• Target Range (Peritoneal Dialysis Patients): More than 2.0.
• Test Procedure (Hemodialysis): Blood samples are taken before and after a dialysis session, and a computer calculates the Kt/V result.
• Test Procedure (Peritoneal Dialysis): Requires a blood sample along with a sample of PD fluid and the volume removed over 24 hours.
• Test Frequency: Monthly for hemodialysis patients and every four months for PD patients or after a prescription change.

A1c — Glycosylated Hemoglobin Test (Hemoglobin A1c)

• Purpose: Measures average blood glucose levels over a two to three month period, primarily for individuals with diabetes.
• Target Range (American Diabetes Association): Less than 7.0 gm/dl for effective blood glucose management in diabetics.
• Test Procedure: Involves a blood sample sent for analysis.
• Test Frequency: Initially conducted upon diabetes diagnosis and then repeated two to four times a year.

Blood Electrolyte Levels

• Purpose: Measures levels of essential electrolytes (sodium, potassium, calcium, phosphorus) in the body, critical for nutrient and waste transport in and out of cells.
• Normal Range: Sodium: 135 to 145 mEq/L, Potassium: 3.5 to 5.0 mEq/L, Calcium: 8.5 to 10.5 mg/dL, Phosphorus: 3.0 to 4.5 mg/dL. Levels may vary for dialysis patients.
• Test Procedure: Requires a blood sample sent for analysis.
• Test Frequency: During stages 3, 4, and 5 of kidney disease, when a renal diet is prescribed or for individuals on dialysis.

Understanding these laboratory tests and their results empowers your healthcare team to make informed decisions regarding your treatment and dietary adjustments. If you have questions about your test results or need further information, don’t hesitate to consult a member of your kidney care team or access your lab results via the American Dialysis Centers.