How to Read Your Dialysis Lab Results

Dialysis patients typically have blood drawn once a month, with results that influence medication adjustments, dietary recommendations, and treatment settings. Most patients receive a printout of their lab results without much explanation. Here is what the most important numbers actually mean.

Kt/V — Is your dialysis dose adequate?

Kt/V is the single most important measure of whether you are getting enough dialysis. The formula compares the volume of blood cleared of urea (a waste product) to your body's total water volume.

Target: 1.2 or higher for three-times-weekly dialysis

A Kt/V below 1.2 means you may be under-dialyzed, which is associated with higher mortality, more hospitalizations, and worse quality of life. If your Kt/V is consistently below 1.2, ask your care team why and what can be changed — longer sessions, higher blood flow rate, or a different type of dialyzer.

Potassium (K+)

Potassium is regulated by the kidneys. When kidneys fail, potassium accumulates between dialysis sessions. High potassium (hyperkalemia) can cause fatal heart arrhythmias without warning.

Normal range for dialysis patients: 3.5–5.5 mEq/L pre-dialysis

Values above 6.0 are dangerous. If your potassium is consistently elevated, your care team will likely recommend reducing high-potassium foods (tomatoes, potatoes, oranges, bananas) and possibly adjusting your dialysate (the fluid used during treatment).

Phosphorus

Phosphorus builds up in dialysis patients because dialysis only removes a fraction of what the kidneys would normally clear. Chronically elevated phosphorus weakens bones, hardens blood vessels, and is associated with higher cardiovascular mortality in dialysis patients.

Target: 3.5–5.5 mg/dL

Management involves a combination of dietary restriction (less dairy, nuts, processed foods), phosphate binders taken with meals, and adequate dialysis. If your phosphorus is persistently high, discuss whether your binders are working and whether dietary adjustments are realistic for you.

Calcium

Calcium and phosphorus interact in dialysis patients. Many patients develop hyperparathyroidism — where the parathyroid gland produces excess hormone trying to regulate calcium — which further disrupts bone metabolism.

Target: 8.4–10.2 mg/dL

Corrected calcium levels outside this range should prompt a conversation about parathyroid hormone (PTH) levels and potential treatment adjustments.

Hemoglobin / Hematocrit

Dialysis patients commonly develop anemia because failing kidneys produce less erythropoietin (EPO), the hormone that signals the body to make red blood cells. Low hemoglobin causes fatigue, shortness of breath, and reduced exercise tolerance.

Target hemoglobin: 10–12 g/dL

Most dialysis patients receive erythropoiesis-stimulating agents (ESAs) — synthetic EPO — by injection. If your hemoglobin is consistently below 10, ask whether your ESA dose is appropriate or whether there is an iron deficiency contributing.

Albumin

Albumin is a protein that reflects nutritional status. In dialysis patients, low albumin is one of the strongest predictors of mortality — even more predictive than Kt/V or other dialysis adequacy measures.

Target: 4.0 g/dL or higher

If your albumin is below 3.5, it is a serious flag. Talk to your renal dietitian about protein intake. Some patients do not eat enough protein because they are trying to restrict other dietary components; getting the balance right requires working closely with someone who knows dialysis nutrition.

PTH (Parathyroid Hormone)

Parathyroid hormone becomes chronically elevated in most dialysis patients as the parathyroid glands work harder to maintain calcium balance.

Target: 150–600 pg/mL (secondary hyperparathyroidism management range)

Extremely high PTH (above 1,000) is associated with bone disease, fractures, and cardiovascular complications. Treatment may include active vitamin D analogs, calcimimetic medications, or in severe cases, parathyroidectomy.

What to ask at your monthly review

When your labs come back, these are useful questions regardless of where your numbers fall:

1. What changed from last month, and why?
2. Is anything outside target range, and what is the plan?
3. Is my Kt/V consistently at or above 1.2?
4. What can I do differently with my diet to improve these numbers?
5. Are my medications optimized for where these numbers are?

Your care team should walk through labs with you monthly. If they are not doing this, ask for it explicitly — you have the right to understand what is being measured and why.