your guide to basic blood panels
Complete Blood Count (CBC) with differential - this is probably the most common test I order especially if someone is coming in with symptoms of fatigue, heavy periods, or lightheadednes.
A CBC stands for complete blood count - it looks at both your red blood cells (carries oxygen throughout your body) and white blood cells (immune response cells). This little test can tell me a lot! I typically use this test to check for anemia or infections but can also detect some forms of cancer.
The red blood cells help me determine if you have anemia and the size and shape help tell me what type. Anemia can cause some of the most common symptoms I see in my office - fatigue, headaches, insomnia, brain fog, heavy periods, and lightheadedness.
The white blood cells can tell me if you have a current infection and what type: elevated neutrophils = acute infection often bacterial; lymphocytes = usually viral or bacterial infection but can be from chronic infections, autoimmune conditions, and blood cancers; eosinophils = often allergic response or a parasite; basophils = inflammation and allergies.
CMP - this is probably my favorite basic blood test! The comprehensive metabolic panel gives us docs a snapshot of how your major organs are functioning.
Liver Function:
--Alanine aminotransferase (ALT/SGPT) - mild/moderate elevation most associated with alcohol excess but also mildly high with “fatty liver”. High levels associated with liver disorders.
--Aspartate aminotransferase (AST/SGOT) - mild/moderate elevation associated with “fatty liver” and metabolic disease but can also be elevated due to alcohol excess. High levels associated with liver disorders.
--Alkaline phosphatase - associated with liver disease but may also be related to bone disease.
--A/G ratio (albumin/globulin) - elevated level is associated with liver disease
--Bilirubin (waste product of blood that normally should be processed by the liver - high levels could signal liver disease and can make the skin yellow - jaundiced).
Kidney function:
--eGFR - estimation of your kidney filtration rate, low level associated with liver disease
--BUN - normally filtered out of kidney, high levels may mean impaired kidney function
--A/G ratio - low number may be associated with kidneys
--Creatinine - associated with kidney function and muscle mass
--BUN/creatinine ratio (related to blood flow to kidneys - may signal dehydration or congestive heart failure)
Electrolytes and minerals: sodium, potassium, bicarbonate (CO2), chloride. Calcium - important mineral for bones and muscle function, typically it is well regulated even in a low calcium diet so an imbalance can mean parathyroid dysfunction or vitamin D deficiency
Blood sugar - ideally fasting; helps check for diabetes
All about the lipid panel
What does cholesterol do in our body? Cholesterol is the building blocks of many of our hormones and is important for our cell membranes
2 main types of cholesterol - LDL (low density lipoproteins) and HDL (high density lipoproteins)
Low Density Lipoproteins (LDL) - this is considered the “bad cholesterol” if elevated. If you have too much of this cholesterol then it may stick to the walls of your arteries and build plaque. Over time this leads to atherosclerosis which makes you more. Desirable levels are at below 129, borderline high at 230-159 mg/dl, high at at 160-189 mg/dl, and very high at or above 190 mg/dl.
High Density Lipoproteins (HDL) - this is considered the “good cholesterol” and optimal levels are around 60 mg/dl or higher. Levels less than 40 mg/dl for men and 50 mg/dl for women are at an increased risk of heart disease.
Triglycerides - This is a type of fat that circulates in our blood system and is actually more associated with excess carb intake at a meal and insulin resistance. When you eat a high carb meal and need to store some of the excess calories as fat, your liver converts it to triglycerides and then this travels to your fat cells for storage. Triglycerides can come from high fat meals as well or when your body is trying to utilize stored fat for energy. High triglycerides is associated with cardiovascular disease and diabetes. Normal triglyceride levels should be 150 mg/dl or less, borderline levels are at 151-200 mg/dl, high levels are 201-499 mg/dl and very high is greater than 500 mg/dl.
There are several ways to monitor your blood sugar and the mains ones are discussed below. Although we primarily just use the fasting blood glucose and the hemoglobin A1c, there are other labs that we occasionally use to get more insight in how your body is handling sugar and insulin.
1. Fasting blood glucose - gives a snapshot of how your blood sugars are after fasting. Should be lower than 100, prediabetes range is 100-125, diabetes range is 126+
2. Hemoglobin A1c - this approximates your blood sugar for the past 3 months. The standard reference range is 4-5.6%, prediabetes is between 5.7% and 6.4%, and diabetes is at 6.5% and above. Typically the standard of care for type 2 diabetes is treating to 7% or below but I prefer to work on reversing the condition or bringing back down to prediabetic levels. I find that an A1c in the upper range of normal is still a beginning sign of insulin resistance and I typically aim for below 5.4% to maintain health blood sugars and help those with weight loss goals.
3. Fructosamine - glycated protein (sugar + protein) -> estimates the average blood glucose over the past 2-3 weeks.
4. Insulin - typically measured fasting to check for insulin resistance. Insulin is a hormone that is typically released after a meal to help get glucose into cells that need it. When there is too much glucose on a regular basis the cells become resistant to the effects of insulin and this leads to a rise in insulin in the blood and is associated with higher blood sugars.
Thyroid labs:
The 3 main thyroid labs I run are the TSH (thyroid stimulating hormone), the free T4 (fT4) and free T3 (fT3). There are additional labs that I often run to check for autoimmunity that are not included here.
Thyroid Stimulating Hormone (TSH) - this hormone comes from the pituitary gland to send signals to the thyroid to increase free T4 into the blood stream. When free T4 is high, this will signal back to the brain to decrease the production of TSH. Therefore, if TSH is high, there is not enough circulating free T4 so the brain keeps increasing the level of TSH to try to get the thyroid gland to produce more free T4. A high TSH is seen in hypothyroidism which is associated with fatigue, weight gain, constipation, dry skin, brittle nails, and feeling cold all the time.
Free thyroxine (fT4) - this is the hormone created in the thyroid gland that helps support metabolic processes. T4 is the inactive form of the thyroid hormone and is circulated throughout the body then converted to the active form, free T3, where it is needed in the body. Levels are often low or normal for hypothyroidism.
Triiodothyronine or free T3 (fT3) - This is the active form of the thyroid hormone. It is made in small amounts in the thyroid and most is converted from free T4 in the body where it is needed. Levels can be normal or low in hypothyroidism.