Helping New Nurses with Common Lab Values

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Nursing professionals conduct and analyze laboratory tests on a daily basis. As a result, experienced nurses readily retain and recall common values of lab results. Those new to nursing, however, may encounter stumbling blocks along the way.

As a nursing educator or leader, it’s important for you to remember that new or non-experienced nurses need time to build their rote memory of basic lab values. By implementing small, helpful measures, such as portable placards or mini pamphlets, you can ease the learning process while reducing the potential for misdiagnoses.

Below are some of the more common laboratory tests, what they measure and the common lab values for each test. If a new nurse comes upon values that wildly deviate from the norm, he or she will be more confident to accurately report the prognosis.

Red blood cells

This oxygen-carrying cell will let the nurse or physician know if a patient is getting enough oxygen in the body. Red blood cells contain hemoglobin, the oxygen carrier.

Normal value: 4.2-6.2 million cells per microliter (equivalent to a cubic millimeter or mm3).


Leukocyte count, or white blood cell count, will diagnose infection in the body. It will determine the number of WBCs in the body.

Normal value: 5,000-10,000/mm3.


This tests the volume percentage of red blood cells in the blood. It can alert medical professionals to possible problems, such as chronic obstructive pulmonary disease (COPD), bone marrow abnormalities, dehydration, anemia and more.

Normal value: 38%-54%.


A person with diabetes will need to have this blood test performed several times a year. The values will determine the diabetic patient’s course of treatment.

Normal value: 12-18 g/dL.


Platelets help the blood to clot. This test will determine the number of platelets that are in the body. This count could also play a part in using bone marrow or chemotherapy for the treatment of other conditions.

Normal value: 150,000-450,000/mm3.

Uric acid

This test will determine any heightened level of uric acid. This test is important in cases of radiation, chemotherapy and gout.

Normal value: 2.7-8.5 mg/dL.

Prothrombin time

Prothrombin time, or PT, results will determine the effectiveness of blood thinning agents (anticoagulants). The results will determine the dosage given to the patient, which could change weekly. A PT can also determine a bleeding problem.

Normal value: 9.5-11.8 sec.

Partial thromboplastin time

This lab test will alert the nurse or physician of how long it takes for a patient’s blood to clot. This test is performed on those with a bleeding disorder.

Normal value: 30-45 sec.

Sedimentation rate

The ESR, or sedimentation rate, signals inflammatory conditions, such as arthritis.

Normal value: C20-C30 mm/hr.


This measures the electrolytes and minerals in the blood, which can signal problems with the nerves, muscles, kidneys and more. This test will also determine dehydration, a common condition.

Normal value: 3.5-5.0 mEq/L.


A BUN, or blood urea nitrogen, test checks the functioning of the kidneys.

Normal value: 6-20 mg/dL.


This lab test is done to see how well your kidneys are functioning. Kidneys remove the creatinine from the body. If creatinine levels are high, the kidneys are not doing their job.

Normal value: 0.5-1.3 mg/dL.

Because laboratory test results are affected by factors regarding the patient’s pre-testing behavior, such as consumption of certain medication and/or foods, it is important for nurses to ask patients if they followed protocol before the examination. Some irregular results may just be a matter of patient oversight.

edited by Kevin Phang

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