Understanding Lab Values

The Importance of Understanding Lab Values

Why is understanding lab values an important skill for a caregiver? After all, the doctor reads the lab work and tracks what is going on with your family member.  Why not trust them to handle that part of the care alone?

Advantages of Knowing Lab Values

Understanding lab work is not your responsibility as a caregiver; however, knowing lab values has its advantages.

  1. By knowing lab values, you can predict what may happen next to take appropriate action.
  2. Doctor’s don’t always catch changes in values that are unique to individuals. Family members do. Bring significant changes in lab values to the doctor’s attention if they don’t notice. I have prevented serious medical problems that doctors overlooked twice by making those calls.
  3. When you know lab values have returned or remain at normal, it’s reassuring. Furthermore, if your family member is ill, seeing the lab values improve brings you hope and encouragement.

Supplies for doing blood draws

Monitoring Lab Values Unlocks the Mysteries of the Body 

I keep home test kits for monitoring kidney, liver, and overall metabolic functions. If I see symptoms that tell me something is not right, I collect a urine specimen and check to see if any values are out of range. I never accept one test because anything can impact a test one time; therefore, I collect another specimen as soon as I can practically do so. If it shows the same information, then I know I likely am seeing a problem developing.

I either call the doctor to get a recommendation or start with our treatment protocols if I know what to do. By catching changes early, treatment can start before anything significant develops, and a cure can occur quickly.

Understanding Lab Values Unlocks the Mysteries of the Body 

Lab work unlocks the mysteries inside the body. We can’t see what’s happening underneath the skin. However, as a nurse, I’ve learned that what I can’t see from the outside, I can find out from the blood. As blood circulates throughout the body, it picks up enzymes, proteins, and other waste products discarded from the organs. By measuring those cast-offs, we can determine how well the organs are functioning.

When comparing the values from two organs together, you can often see the impact a “sick” organ has on an otherwise healthy organ. The strain placed on a “healthy organ” may cause it to use up more chemicals to complete whatever process it does for the body. At first, it over-produces the chemical to make up for the other organ. After a while, it begins to wear out and under-produces. If you know the normal lab values, you can follow the disease’s progress by the changes you see in the two organs’ chemical waste byproducts.

CBC – Complete Blood Count

A Complete Blood Count (CBC) is one of the most common tests ordered. The test’s purpose is to check the count of all the cells in your blood and identify how many are present.  A CBC includes a count of the red blood cells, white blood cells, platelets, hemoglobin, and hematocrit levels.  If the doctor asks for a differential, it will also include a count of the immature cells present at each development stage.

 Red Blood Cells


 Red Blood Cells – (RBC) Normal range 4.2 -6.1 x1012/L (also called erythrocytes) Are produced by the bone marrow and live about 120 days (4 months). Each RBC makes hundreds of thousands of hemoglobin molecules.  Body tissues, liver, and spleen destroy RBC.


Hematocrit – (Hct) The hematocrit is a percentage of RBCs in the total blood volume (i.e., red blood cells floating around in the blood plasma). To determine the number of RBCs, they are separated from blood plasma and counted as a percentage of everything left over to determine how they compare. A low hematocrit indicates fewer RBCs; a higher hematocrit means more RBCs.

White Blood Cells

White Blood Cells – (WBC) (also called leukocytes) Preferred range is 5.0 -10.0 x103. White blood cells are produced by bone marrow like RBC. Their job is to protect the body against infection. WBCs attack harmful organisms coming against us tries to destroy them, cleans up the carnage after the battle, create antibodies to protect us from that enemy for the future, and stimulates the bone marrow to get us ready for the next fight! Increased levels of WBC indicate inflammation, infection, autoimmune disorders, or leukemia. A drop in levels indicates possible prolonged suppression of the bone marrow.


Platelets – Although bone marrow also produces platelets, they are different from red and white blood cells. Instead of keeping things moving along, the smallest of the three blood cell siblings has the job of clogging up the works.  Unlike the white and red blood cells that keep blood flowing along, their little brother, platelet’s job, is to stick himself to any injured areas, form a clot, clump a group of clots together, and initiate the healing process. Platelets are produced by the bone marrow but stored in the spleen till needed. There are usually, 20% of our platelets in storage at any given time.


Hemoglobin – Hemoglobin is produced by red blood cells and uses iron to transport up to four oxygen molecules at a time.  It also carries carbon dioxide, which helps to maintain the acid/base balance.

Understanding Lab Values Related to Blood Cell Counts

CBC Values

Column 1 = Element being measured

Column 2= Average value for healthy male

Column 3 = Average value for healthy female

Column 4 = Critical Value. The number that represents the dangerous levels a person can fall within.

Checking blood sugar at home is one way to monitor how well a diabetic's insulin dose is handling their dietary intake, exercise level, illness stability, and daily activities.
Checking blood sugar at home is one way to monitor how well a diabetic’s insulin dose is handling their dietary intake, exercise level, illness stability, and daily activities.
Follow these links to videos showing how to use home testing kits and to perform quality control testing.

How to Use a Lancet Device

How to Prick Finger Tips with a Lancet Device for Checking a Blood Sugar

How to Perform a Quality Control QC Test on a Glucometer 

Metabolic Panel

The metabolic panel is one of the most common blood tests ordered and may include 8 or 14 tests.  A basic panel has eight tests and looks primarily at electrolytes and kidney function in addition to glucose and calcium.  A comprehensive metabolic panel includes an additional six tests that focus on liver function and protein levels. The accumulation of all this information provides your healthcare provider with a wealth of information about your family member’s metabolism.

Why is Metabolism Important?

Metabolism is how we convert food into energy and use that energy to make the body function properly. That process is essentially a chemical one and occurs through a series of organs doing their part to mechanically break down the food and chemically decompose it to energy. If our organs don’t work correctly so that the chemicals get filtered in the right amounts, our body suffers the consequences. The Metabolic Panel tells us what organs are not doing their part if that happens.

The metabolic panel has five primary categories. Miscellaneous (Glucose, Calcium), Electrolytes (Sodium, Potassium, Bicarbonate, Chloride), Kidney Function, (Blood Urea Nitrogen, Creatinine), Proteins, (Albumin, Total Protein), and Liver Tests (Alkaline Phosphatase, Alanine aminotransferase, Aspartate aminotransferase, Bilirubin).

Using Home Test Kits to Monitor Labs Values

Once you understand lab values, you’ll want to keep an eye on them yourself. One way to monitor lab values is to buy home monitoring test kits. Since you don’t have a lab at home to do blood tests, you are limited to testing urine or drops of blood on small chemical reagent strips. However, these are great screening tools.  Keep in mind these tests are not as sensitive as the ones done in a laboratory, and therefore, you may get false positives at times (i.e., the test might read as positive when it’s actually negative).  If you get a positive reading, always do a second test to confirm what you got and then notify your doctor.  Also, confirm your test kit has not expired.  If the chemicals you’re using are old, they might not react correctly.

Many Types of Kits Available

In today’s marketplace, many types of test kits are available for a variety of testing options. When I am suspicious that my husband might have a urinary tract infection, I use a test kit to check. By dipping a strip treated with special chemicals in urine, I can tell by the results if he has a possible infection. The results allow me to increase his fluid intake and take other actions to flush out his urinary system. Most of the time, I can clear up the problem without antibiotics. That’s a win/win for us.  Therefore, I recommend using testing kits at home as a monitoring practice.

MUST Follow Directions Closely

Most home test kits are easy to use; however, you must follow directions precisely to be effective. Don’t be tempted, for example, to use the strips after the expiration date.  The chemicals won’t give accurate results. Throw them away! Always write the date you open the box on the package immediately. Throw away the contents remaining based on the manufacturer’s recommendations.

Home Health Monitoring Helps You Act Quickly  

Home testing is a guideline that helps you to monitor your level of wellness and allows you to take corrective action quickly if needed.  However, its effectiveness is only as good as your willingness to follow the kit’s instructions correctly. Taking shortcuts only hurts you or your family member.

  • Keep the test strips and chemicals dry and in a dark place.
  • Write the date opened on the container and throw it away by the expiration day.
  • Time the test accurately
  • If you get an abnormal reading, do a second test, check to make sure that there is no other explanation for the abnormal result, and if not, notify the doctor of your findings.

Metabolic Panel Values

Metabolic panel values
Metabolic Panel Values


Metabolic Panel Values – Column 1: represents the element being tested,

Column 2:  the average normal for the general population of adult males,

Column 3: the average normal for the average population of adult females.

Column 4: critical values.  When numbers are in this range, patient values are dangerously low or high.

To Understand Lab Values, You Need to Know What You’re Testing


Glucose – Glucose is the primary energy source for the body’s cells. A steady supply must be available for use, and a relatively stable glucose level maintained in the blood.  Insulin transfers extra glucose from the blood to muscle, fat, and liver cells for storage, and the body burns it as needed for energy.


Calcium – Calcium is one of the most important minerals in the body. It is essential for the proper functioning of muscles, nerves, and the heart and required for blood clotting and bone formation. Calcium levels are regulated by the parathyroid gland and by Vitamin D.


Sodium – Sodium is vital to normal body function, including nerve and muscle function. It is the most abundant electrolyte outside the cells and is essential to maintaining the extracellular fluid’s osmotic pressure for acid/base balance.


Potassium – Potassium is necessary for cell metabolism and muscle function, and for helping to transmit messages between nerves and muscles.  Abnormal potassium levels can significantly affect the heart muscle’s electrical impulses and lead to painful cramping in skeletal muscles. It plays a significant part in transforming glucose into energy and amino acids into proteins.

Bicarbonate (Total CO2)

Bicarbonate (Total CO2 Bicarbonate helps to maintain the body’s acid-base balance (pH). It provides the primary buffering system for the extracellular fluid system that flows throughout the body with CO2 bound to protein or physically dissolved.


Chloride – Chloride participates with sodium in maintaining the water balance and regulating osmotic pressure. Chloride contributes to gastric acid (hydrochloric acid) for digestion and activates enzymes to break down our food.  We get most of our chloride from food in the form of salt (sodium chloride). The kidneys get rid of any unneeded chloride using our elimination processes-i.e., urine output.

Blood urea nitrogen (BUN

Blood urea nitrogen (BUN) – The body cannot store protein.  Amino acids and nitrogen make proteins from the food we eat. Urea is a nonprotein nitrogen (NPN) compound formed in the liver from ammonia and excreted by the kidney as a protein metabolism byproduct. Other NPN compounds excreted by the kidneys include uric acid and Creatinine. Evaluating uric acid and creatinine levels together is a good way to measure kidney functioning. As the BUN level rises, its a clear indication that the kidney function is declining.


Creatinine – As mentioned above, Creatinine is another waste product of protein breakdown and often is a byproduct of muscle use.  Creatinine is filtered out of the blood by the kidneys, so blood levels are a good indication of how well the kidneys are working.


Albumin – Albumin is a small protein made by the liver; it makes up about 60% of the blood’s total protein.

Total Protein

Total Protein – Total Protein measures albumin and all other proteins in blood; proteins are important building blocks of all cells and tissues and are essential for body growth, development, and health.

Alkaline phosphatase (ALP)

Alkaline phosphatase (ALP) – An enzyme found in bone, the liver, and other tissues. Liver disease or bone disorders commonly cause elevated levels of ALP in the blood.

Alanine aminotransferase (ALT, SGPT)

Alanine aminotransferase (ALT, SGPT) – An enzyme found mostly in the cells of the liver and kidney; a useful test for detecting liver damage

Aspartate aminotransferase (AST, SGOT)

Alanine aminotransferase (ALT, SGPT) – An enzyme found mostly in the cells of the liver and kidney; a useful test for detecting liver damage


Bilirubin – An orange-yellow pigment, a waste product primarily produced by the normal breakdown of heme; heme is a hemoglobin component found in red blood cells (RBCs). The liver removes bilirubin from the body after processing.