Labs to Know for NCLEX Review

Lab values to know for NCLEX and as a nurse or nursing student!

This review will target the most important lab values you need to know for NCLEX and as a nurse.

When you take the NCLEX exam there is a high probability you will have some type of lab value question.

WHY? Because almost every patient that walks through the doors of a hospital will have blood work drawn, and as the nurse you will need to know about the common blood tests ordered and their normal lab value ranges. Therefore, the NCLEX wants to make sure you have competent knowledge in this area before you start working as a licensed nurse.

What are the common blood tests?

Metabolic Panel (BMP or CMP): This test can be basic or comprehensive, and it assesses fluid and electrolytes status along with glucose, renal and liver function.

Complete blood count (CBC): assesses the amount of cells in the blood….platelets, white blood cells, red blood cells, hemoglobin, and hematocrit.

Arterial Blood Gases (ABGs): assesses for acid-base imbalances in the body…this test is very important for patients with respiratory or metabolic conditions.

Coagulation Levels: assesses clotting times (PT/INR or aPTT)…this is very important for many blood disorders and for patients who are on anticoagulants.

Lipid Panel (Lipid Profile): assesses for the risk of cardiovascular disease by measuring lipoproteins, triglycerides, cholesterol.

Hemoglobin A1C: assesses average blood glucose level during the past 3 months…great test to check glucose management in patients with diabetes.

Drug Levels: assesses the amount of drug present in a patient’s system. Many patients are on drugs that have a very narrow therapeutic drug range. Therefore, this test is helpful in determining if a drug is subtherapeutic or toxic in a patient’s system.

What to expect on the NCLEX exam with these lab values?

On the NCLEX exam, you will be given lab values that are noticeably abnormal. For example, a normal Magnesium level is 1.5-2.5 mg/dL. On the NCLEX, it is highly unlikely they will ask you to choose an abnormal lab result of a Magnesium level that is 1.4 mg/dL or 2.6 mg/dL because these results are way too close to normal. They will give you something you will notice like <1 or >3 mg/dL.

Another important thing to point out is that normal lab value ranges vary depending on the laboratory. So, don’t get confused on if one text says a normal Magnesium level is 1.4-2.6 mg/dL, while another text says a normal Magnesium is 1.5-2.5 mg/dL. Remember to be familiar with the average range and keep in mind NCLEX will test you on something that is very abnormal.

How am I going to remember all of these lab values as a nurse?

When you work as a nurse you will be encountering these labs every day, and pretty soon you will be able to recite them in your sleep.

Plus, when you are looking at your patient’s results you will be able to see the normal reference range from the lab that processed the blood specimen. This will tell you the exact normal range and how abnormal this lab result is.

Lecture Review on Lab Values

Labs to Know for NCLEX and as a Nurse

Metabolic Panel

Glucose: 70–100 mg/dL

Calcium: 8.5–10.5 mg/L

Chloride: 95-105 mEq/L

Magnesium: 1.5-2.5 mg/dL

Phosphorus:2.5–4.5 mg/dL

Potassium: 3.5-5 mEq/L

Sodium: 135-145 mEq/L

BUN: 5-20

Serum creatinine: 0.6–1.2 mg/dL

Total Protein: 6.2–8.2 g/dL

Albumin: 3.4–5.4 g/dL

Bilirubin: 0.1-1 mg/dL (less 1) (formed with the breakdown of RBCs…high levels in patients with jaundice)

— These are 3 enzymes found in the liver. If elevated, it can indicate liver problems and other diseases.—

• ALP (alkaline phosphatase): 40-120 U/L (international units per liter)
• ALT (alanine transaminase): 7 to 56 U/L
• AST (aspartate transaminase) 10-40 U/L

*this blood test can be ordered as a BMP (basic metabolic panel) or CMP (comprehensive metabolic panel). The CMP will include the liver function.

Complete Blood Count

RBC: 4.5–5.5 million

WBC: 5,000–10,000

Platelets: 150,000–400,000

Hemoglobin:

• 12–16 g/dL (women)
• 14–18 g/dL (men)

Hematocrit:

• 37 – 47% (women)
• 42 – 52% (men)

Arterial Blood Gases (ABGs)

pH: 7.35-7.45

pCO2: 35-45 mmHg

HCO3: 22-26 mEq/L

pO2: 80-100%

O2 sat: 95-100%

Coagulation Levels

INR/PT:

• PT (prothrombin time): 10-12 seconds (normal level for patients not on Warfarin)
• INR (international normalized ration): Less than 1 (normal level for patients not on Warfarin).
  • When a patient is taking the anticoagulant Warfarin the INR should be 2-3.
  • The INR level is calculated from the PT level.

aPTT (activated partial thromboplastin time):

• Normal 30-40 seconds (not on Heparin)
  • If the patient is on Heparin, the aPTT needs to be 1.5 to 2.5 times the normal range.

Lipid Panel (risk for cardiovascular disease)

LDL (low density lipoprotein):  <100 mg/dL (want it LOW)

HDL (high density lipoprotein): >60 mg/dL (want it HIGH)

Total Cholesterol: <200 mg/dL

Triglycerides: <150 mg/ dL

Hemoglobin A1C

• 4-6% (target for patients without diabetes)
• <7% (target for patients with diabetes)

Drug Level Ranges

Digoxin: 0.5-2 ng/mL

Carbamazepine: 4-10 mcg/mL

Dilantin: 10-20 mcg/mL

Theophylline: 10-20 mcg/mL

Phenobarbital: 15-40 mcg/mL

Lithium: 0.5-1.2 mmol/L

Valproic Acid: 50-100 mcg/mL

References: