Understanding your Blood Work

Have you ever gotten blood work done, only to be told that everything looks good, yet you were left confused about what tests were performed and what they actually measure? You’re not alone because I’ve definitely been there myself! 

In this blog post, I will provide a brief overview of the most common blood tests, including what they represent and why they are typically run.

CBC: stands for Complete Blood Count. This looks at our red blood cells and our white blood cells. Generally, it is most commonly used to look for anemia and infections but can be used for other medical conditions. What you will find in a CBC are:

• Red Blood Cells (RBC): these cells are what carries oxygen to all the tissues and organs in our body. 

• Hemoglobin (Hb): the actual component of a red blood cell that carries the oxygen. 

• Hematocrits (Hct): measures how much of your blood is actually made up of red blood cells. Our blood is made up of red blood cells, white blood cells and platelets that are all suspended in plasma. Hematocrit looks at the volume percentage of red blood cells in our blood. 

• Mean Corpuscular Volume (MCV): looks at the size of red blood cells. A high MCV often point towards a vitamin B12 or folate deficiency. A low MCV often points towards an iron deficiency. 

• Mean Corpuscular Hemoglobin (MCH): looks at the average amount of hemoglobin in a single red blood cell. 

• Mean Corpuscular Hemoglobin Concentration (MCHC): is the average concentration of hemoglobin in our red blood cells. 

• Red Cell Distribution Width (RDW): looks at the variation in the size of our red blood cells. 

• Platelets: are another component of our blood. It helps our blood to clot, so it stops bleeding after an injury. If you have low platelets you can have excessive bleeding, but high platelets can also lead to clotting disorders. 

• • White Blood Cells (WBC): these are cells that fight off infections. Here you will see the total number of WBCs, but there is also a breakdown of different types of white blood cells. 

• Neutrophils: are the most common type of white blood cells and generally the first responders to infection, especially bacterial infections. 

• Lymphocytes: typically make up 20-40% of our white blood cells. They include B cells and T cells which are important to mount an immune response. 

• Monocytes: help remove dead and damaged cells. They are the clean-up crew.

• Eosinophils: are mostly involved in allergic reactions and fighting parasites. 
• Basophils: are present in the smallest amount among white blood cells, typically making up less than 1% of total white blood cell count. They are particularly involved in the immune response for allergic reactions and asthma. 

Ferritin: is used as a marker for iron storage. It is a protein that stores iron in our body and can give us an idea of how much iron we have in reserve. However, ferritin can also be a marker of inflammation so may be falsely elevated. This is why it is important to run it with other iron markers and other inflammatory markers (ex: ESR and CRP) to better understand what the value is representing. 

Iron: measures the amount of iron in your blood. About 70% of our body’s iron is found in our red blood cells which is essential for transporting oxygen to our tissues and cells. Low levels can indicate anemia, whereas high levels could indicate liver disease. 

TIBC: stands for Total Iron Binding Capacity. This measures how much iron your body can carry. A high TIBC could indicate iron deficiency since your body is trying to increase its capacity to carry more iron. Low TIBC are generally seen with liver diseases and chronic inflammation.  

Transferrin Saturation: is expressed as a percentage. Transferrin is a protein that carries iron in the blood. Therefore this test looks at how much transferrin is actually holding iron. 

Vitamin B12: looks at the amount of vitamin B12 in your blood. Is an important component of red blood cell production and is important for nerve health. Low levels can lead to symptoms of fatigue and brain fog, as well as neurological symptoms. \

Vitamin D: looks at the amount of vitamin D in your blood, generally by measuring 25-hydroxyvitamin D (Vit D 25-OH). Vitamin D is important for bone health, immune function, energy and is involved in many other processes. 

Fasting Glucose: represents the amount of glucose in your blood after a period of fasting (generally after fasting overnight). Higher levels can indicate insulin resistance or diabetes. 

HbA1C: is a marker for the average amount of glucose attached to your red blood cells over the past 3 months. This marker is used to diagnose pre-diabetes and diabetes. 

Fasting Insulin: represents the amount of insulin in your blood after a period of fasting. Insulin is a hormone that is released from the pancreas that essentially takes the glucose from your blood and brings them into your cells to use it as fuel (energy). High fasting insulin levels can indicate insulin resistance. 

ESR: stands for Erythrocyte Sedimentation Rate. It is a marker for general inflammation in the body. 

CRP: stands for C-Reactive Protein. It is a protein made by your liver in response to inflammation. It is a marker for general inflammation but can be related to the gut and the cardiovascular system.

Urate: also known as uric acid. High levels can indicate gout or kidney disease. It can also be a marker for insulin resistance and gut bug health. 

Total Cholesterol: is the overall amount of cholesterol in your blood. High levels can increase your risk of cardiovascular disease. 

HDL: stands of High-Density Lipoprotein. Often referred to as our “good” cholesterol. It helps remove other forms of cholesterol from our blood stream. It is associated with lowered risk of heart disease, however if too high, it can indicate oxidative stress. 

LDL: stands for Low-Density Lipoprotein. Often referred to as our “bad” cholesterol. High levels increase the risk of heart disease and stroke. 

Triglycerides: is a type of fat that circulates in our blood. They are used for energy. High levels can contribute to the hardening of the artery walls (arteriosclerosis) which can increase the risk of heart disease and stroke. 

Non-HDL cholesterol: is a value that includes all the “bad” cholesterol including LDL and VLDL (very low-density lipoprotein). 

TSH: stands for Thyroid Stimulating Hormone. This hormone stimulates your thyroid to make thyroid hormones. Higher levels can indicate that you aren’t making enough thyroid hormones (more TSH is being released from the pituitary gland to tell the thyroid to make more thyroid hormones). High TSH can indicate hypothyroidism. Low TSH can indicate hyperthyroidism; a condition where we have too much thyroid hormone. 

eGFR: stands for Estimated Glomerular Filtration Rate. It is a measure looking at how well your kidneys are working and filtering blood. Lower levels indicate impaired kidney function. 

Creatinine: is a waste product from creatine which is important for muscle metabolism. The kidneys filter creatinine from the blood and is excreted through the urine. It is used as a marker for kidney function. Elevated levels can indicate kidney disease. 

ALT: stands for Alanine Aminotransferase. It is an enzyme primarily found in the liver. Elevated levels can indicate liver damage or inflammation.

AST: stands for Aspartate Aminotransferase. It is an enzyme found in various tissues such as the liver, the kidneys, the heart, and in muscles. Elevated levels can indicate damage to the organs mentioned. 

ALP: stands for Alkaline Phosphatase. It is an enzyme found in the liver, the bile ducts, the gut, the bones and in the kidneys. Elevated levels can indicate damage to the organs mentioned. 

GGT: stands for Gamma-Glutamyl Transferase. It is an enzyme primarily found in the liver and the biliary system. Elevated levels can indicate liver disease or bile duct obstruction. It can also indicate oxidative damage.

LDH: stands for Lactate Dehydrogenase. It is an enzyme found in most tissues in your body. It is released into the bloodstream when cells are injured. Therefore it is a marker for tissue damage. 

Bilirubin: is produced from the breakdown of red blood cells. The liver processes bilirubin to be excreted in the bile and in the urine. Elevated levels can indicate liver dysfunction or hemolysis (an increased breakdown of red blood cells). Bilirubin has a yellow pigment to it, hence why we can see signs of jaundice with elevated levels. 

Sodium: measures the concentration of sodium in your blood. High levels can indicate dehydration, kidney disease or excessive salt intake. Low levels can indicate overhydration, kidney or liver disease, heart failure or due to certain medications. 

Potassium: measures the concentration of potassium in your blood. High levels can indicate kidney failure or excessive dietary intake. It can also be due to potassium-sparing diuretics. Low levels can indicate low dietary intake, kidney disease, diuretic use, diarrhea and more. 

Chloride: measures the concentration of chloride in your blood. High levels can indicate dehydration, kidney disease. Low levels can be due to kidney disorders, vomiting or diarrhea, medication, and more. 

When interpreting your blood work results, it is important to look at all the results together rather than at each test in isolation. Each marker can provide valuable information; however, it is only when done with other tests that we can get a much better picture and understanding of what’s going on. That is one thing that I love about being a Naturopathic Doctor! Running and interpreting blood work is something that I do with almost all of my patients. As they say, test don’t guess! 

There is also a difference between “normal” lab values and optimal lab values. If you have been experiencing a range of symptoms and just not feeling like yourself but have been told that your blood work results are normal and you were subsequently sent home without further assistance, you are sadly not alone in this experience. I have heard this over and over from many of my patients. This is why it is important to consult a practitioner who can look at your blood work from an optimal perspective to identify potential underlying issues, explore additional testing options and then provide an individualized treatment plan for you!