Quick Guide: Decoding Blood Test Results
Even if you’re a CrossFit champ or a marathon maven, getting a regular checkup makes sense. What doesn’t always make sense is the baffling list of medical terms on the blood test results that are often part of routine exams. If you try to take help from “Dr. Google,” you end up deep down a rabbit hole. What the heck is TSH? Apart from the puzzling jargon, the design of bloodwork lab reports is dismal. One is stuck deciphering highly technical and administrative-looking documents that make tax forms look like greeting cards. But do not worry. You can make sense of your blood test results.
We don’t want to bore you with a comprehensive glossary of technical terms but attempt to provide basic definitions and a better sense of how the information on a typical blood test report is presented and organized so that you can interpret your blood work with more confidence.
“Normal” and “Abnormal” results
Before we go any further, we have to debunk the overrated “normal’ and “abnormal” labels. You may notice that there may be a few values that are often outside the “normal” range. This is a common source of concern for many. For most blood routine tests, the standard ranges were determined decades ago based on soldiers’ studies. And even though reference ranges for some tests now vary by gender and other categories, those scales are rarely specific enough to correlate to a person’s exact age, race, and other circumstances. Different labs, meanwhile, can set their normal range at different levels. The way normal is defined inevitably leaves some people out. The ranges are generally set to correspond with 95 percent of healthy people in a large study group. But some people will always be on the margins. And sometimes, bodies can acclimate to unusual internal circumstances. As your physician, we individualize the results on what they mean to you at this point. We explain what is our patient’s optimal range, which is more nuanced. Even so-called normal levels may be an indication of a problem that’s already taken root and need to be addressed. It’s also important to understand that none of these tests exists in isolation and we need to begin looking at labs in a more nuanced way and understanding the labs in context with each other. There is a lot of human variation, and the context is essential to interpret any result correctly. A “normal” test result doesn’t always rule out medical problems, while an “abnormal” result doesn’t always indicate a problem. Here is a handy guide to commonly used lab tests:
Comprehensive Metabolic Panel (CMP)
The comprehensive metabolic panel (CMP) is a broad screening tool to evaluate your organs’ health and screen for conditions such as diabetes, liver disease, and kidney disease. It helps monitor known conditions, such as high blood pressure, and monitor treatment with specific medications that may affect kidney or liver function.
Kidney function tests: BUN and Creatinine
Blood urea nitrogen (BUN)
Urea is a waste product made in the liver when protein is broken down. This test measures the volume of nitrogen in the blood. High levels can be caused by dehydration or kidney damage, while low levels may be a sign of malnutrition or severe liver damage.
Creatinine
A creatinine test reveals important information about your kidneys. Creatinine is a chemical waste product that's produced by muscle metabolism. Healthy kidneys filter creatinine and other waste products from the blood that leaves your body in urine. If kidneys aren't functioning properly, an increased level of creatinine may accumulate in the blood. A serum creatinine test measures creatinine levels in the blood and estimates how well the kidneys filter. A creatinine urine test can measure creatinine in urine. Low serum creatinine may indicate low muscle mass.
Liver function tests
Liver function tests (LFTs) are done to determine if the liver is functioning normally. These are part of CMP. Elevated numbers can indicate compromised liver function. Abnormal liver function test results don't always indicate liver disease. An additional test, called a GGT, may be added to the liver panel. This test can indicate that there is damage to the liver or surrounding ducts but does not specify what type of damage is present. A typical liver function study includes:
Aspartate phosphatase (AST), also known as SGOT
Alanine aminotransferase (ALT), also known as SGPT
Alkaline phosphatase (ALP)
Total bilirubin
Direct bilirubin
Indirect bilirubin
Albumin
Albumin
Albumin is a protein that is made in the liver and is found in the blood. It is the most abundant protein in the plasma (plasma is the liquid component of your blood that carries cells, protein, and other substances around the body).
Total Protein, Albumin:Globulin ratio
A total protein test is frequently ordered as part of a comprehensive metabolic panel (CMP) when you have a routine health checkup. Total protein measures albumin and globulin. Eating more protein will not increase your total protein test result. Many medications may affect total protein levels.
Low A/G ratio may be caused by:
Overproduction of globulins
Underproduction of albumin
Selective loss of albumin from the circulation
High A/G ratio may be caused by:
Underproduction of immunoglobulins
Usually, the A/G ratio is not a clinically monitored test.
Lipid Panel
The lipid panel is used as part of a cardiac risk assessment to determine your heart disease risk and decide what treatment may be best if you have borderline risk, intermediate-risk, or high risk. The lipid panel results are considered along with other known risk factors of heart disease to develop a treatment plan and follow-up. Additionally, a lipid panel is used to monitor whether the treatment has effectively lowered cholesterol levels.
Total Cholesterol
It is a measure of all the cholesterol in your blood, including HDL and LDL. Total cholesterol should be less than 180 mg/dL. But there’s more to it, as this number needs to be taken in context with triglyceride and HDL levels.
LDL
LDL (Low-density lipoprotein) is the cholesterol that clogs blood vessels. It is called “bad” cholesterol because it can transport lipids into artery walls and harden the arteries. Major prevention trials have demonstrated a linear relation between LDL levels and the coronary event rate.
Absolute values of LDL can be misleading, as the types of LDL that make up the total number matter more, including the amount of small dense LDL particles and high-density LDL particles. Triglycerides and triglyceride-to-HDL ratio can give us additional insight into our cardiovascular health and risk. Overall, shoot for LDL <100 mg/dl, but less than 70 mg/dL is considered optimal by some. And, look at the LDL value in the context of triglyceride-to-HDL ratio, as this ratio is a helpful biomarker for risk of cardiovascular disease and the presence of insulin resistance
Triglycerides
The fasting lipid profile test also measures another particle, which is much more egregious than LDL: triglycerides. It is a type of lipid stored in fat cells when calories go unused. The main reason for high triglycerides is the refined carbohydrates and sugars in your diet. Triglycerides are responsible for storing extra calories and providing your body with energy when it is needed. Triglycerides are a good marker of dietary quality. In our practice, we have seen a significant drop in triglycerides levels in less than one month in patients who eliminate refined and processed foods (refined grains and sugars) and eat whole unprocessed foods rich in fiber.
Triglycerides are a very important marker of metabolic syndrome and insulin resistance. You definitely want them to be <150 mg/dL, but optimal is likely less than <100 mg/dL, or even lower.
HDL
HDL (High-density lipoproteins) are a type of complex made of proteins and fat that carry cholesterol in the blood. HDL particles remove lipids from cells and blood vessels. When cholesterol is in an HDL particle, it is sometimes called “good” cholesterol because HDL scavenges for and ferries LDL cholesterol away from the arteries and back to the liver for redistribution, metabolism, and elimination.
Epidemiological studies have shown that higher concentrations of HDL (>60 mg/dL) are associated with reduced cardiovascular risk. For a given level of LDL, the risk of heart disease increases 10-fold as the HDL varies from high to low. HDL is known for its ability to It’s also known for its anti-inflammatory, antithrombotic, anti-immune, and antioxidative activity. The prevailing dogma for the past 30 years was that high total HDL was cardioprotective because it reflected better clearance of LDL. However, the emerging narrative is that HDL is far more heterogeneous than previously understood. In order for HDL to be cardioprotective, it must be functional. Because of the heterogeneity of HDL, measurement of HDL cholesterol alone does not provide a complete picture of the protective qualities of HDL.
HDL goes down in the setting of insulin resistance, and low HDL is associated with heart disease risk. It should be above 60 mg/dL, but the higher the better.
Total Cholesterol to HDL ratio
For a given level of total cholesterol, the risk of heart disease increases 10-fold as the HDL varies from high to low. Men have double the risk for heart disease if their ratio reaches 9.6:1, and they have roughly half the average risk for heart disease with a cholesterol ratio of 3.4:1.
Together, these numbers provide more information about your coronary heart disease risk than knowing only one of the numbers. The higher the ratio, the higher the risk. Keep the total cholesterol-to-HDL ratio less than 3.5:1, but optimally as low as <2:1.
Triglyceride to HDL ratio
This test is the best way to check for insulin resistance other than the insulin response test. According to a paper published in Circulation, the most powerful test to predict your risk of a heart attack is the ratio of your triglycerides to HDL. If the ratio is high, then your risk for a heart attack increases 16-fold—or 1,600 percent. This is because triglycerides go up and HDL or good cholesterol goes down with diabesity (insulin resistance).
Triglycerides to HDL-cholesterol ratio has been shown to show the strongest association with cardiovascular disease than any other lipid marker or ratio.
The triglyceride to HDL ratio is the best biomarker of small dense LDL, the best biomarker of cardiovascular disease, and the best surrogate marker of insulin resistance and metabolic syndrome.
This is a marker you should focus on. Many experts agree that the triglyceride-to-HDL ratio is one of the best surrogate markers of insulin resistance and metabolic syndrome. If the triglyceride-to-HDL ratio is over 2.5:1 in Caucasians or over 1.5:1 in African Americans, that’s a correlate of metabolic syndrome. Lower is better.
Thyroid Function Tests: TSH, FT4, FT3
The thyroid-stimulating hormone (TSH) test is often the test of choice for initially evaluating thyroid function and/or symptoms of a thyroid disorder. TSH, free T4, and sometimes free T3 may be ordered together as a thyroid panel. High TSH usually indicates underactive [low] thyroid function, while low TSH usually indicates overactive [high] thyroid function. These tests are a "snapshot" of what is occurring within a dynamic system. A person’s thyroid testing results may vary often and may not always indicate a health problem.
Dr. Amar Singh, MD and Dr. Poonam Singh, MD
Complete Blood Count (CBC)
The CBC is a group of tests that evaluate the cells that circulate in the blood, including red blood cells (RBCs), white blood cells (WBCs), and platelets (PLTs). The CBC can evaluate your overall health and detect a variety of diseases and conditions.
Red blood cell (RBC) tests:
RBC count is a count of the actual number of red blood cells in your blood sample. RBCs carry oxygen from your lungs to your entire body. Low red blood cell counts may indicate disorders, such as anemia or blood loss.
Hemoglobin measures the total amount of the oxygen-carrying protein in the blood, which generally reflects the number of red blood cells in the blood.
Hematocrit measures the percentage of your total blood volume that consists of red blood cells.
Red blood cell indices provide information on the physical features of the RBCs:
Mean corpuscular volume (MCV) is a measurement of the average size of your red blood cells.
Mean corpuscular hemoglobin (MCH) is a calculated measurement of the average amount of hemoglobin inside your red blood cells.
Mean corpuscular hemoglobin concentration (MCHC) is a calculated measurement of hemoglobin’s average concentration inside your red blood cells.
Red cell distribution width (RDW) is a measurement of the variation in your red blood cells’ size.
White blood cell (WBC) tests:
WBC count is a count of the total number of white blood cells in your blood sample. WBCs help with immunity, so low counts may be a sign of infection or immune system problems.
There are different types of white blood cells; a blood differential test measures each type: neutrophils, lymphocytes, monocytes, eosinophils, and basophils.
Platelet tests:
The platelet count is the number of platelets in your blood sample. Platelets help your blood clot. Low platelet levels may lead to too much bleeding; high levels may raise your risk of blood clots.
Mean platelet volume (MPV) may be reported with a CBC. It is a measurement of the average size of platelets.
Platelet distribution width (PDW) may also be reported with a CBC. It reflects how uniform platelets are in size.
Fasting Glucose
It is a measure of your blood sugar levels unaffected by a recent meal and can help identify problems with carbohydrate metabolism. Fasting blood glucose is one of the easiest blood biomarkers to track and is highly correlated with metabolic syndrome, cardiovascular risk, dementia, and many other chronic diseases. Blood glucose matters—chronically high levels will damage blood vessels and nerves through several distinct mechanisms. However, to be most valuable, glucose needs to be viewed dynamically—how does it rise and fall in response to certain stimuli (e.g., diet, exercise, sleep).
Once the fasting glucose rises over 100 mg/dl (signifying glucose intolerance; 126 mg/dL or above means frank diabetes), metabolic syndrome is in full force. Try to keep fasting glucose <90 mg/dL.
Hemoglobin A1c (A1c)
Hemoglobin A1c, also called glycated hemoglobin, is hemoglobin with glucose attached. It is a way to measure blood glucose averages over the preceding three months; based on glycation, the process by which glucose molecules attach to hemoglobin in red blood cells (which tend to live around three months, although this varies from person to person). The value is expressed as a percentage of hemoglobin molecules that are glycated.
Even in the face of normal fasting blood sugar, your hemoglobin A1c can be high, because it measures your average sugar, including the effects of all the food you eat throughout the day. We use it to screen for overall blood sugar balance.
The A1c test will not reflect temporary, acute blood glucose increases or decreases, or good control that has been achieved in the last 3-4 weeks. The glucose swings of someone who has "brittle" diabetes will also not be reflected in the A1c. Any condition that affects the quality and quantity of red blood cells (RBCs) and hemoglobin (e.g., iron deficiency, bleeding, hemolysis, etc.) will affect A1c test results. For example, if someone is iron-deficient, the A1c level may be increased, or if a person receives erythropoietin therapy or has had a recent blood transfusion, the A1c may be inaccurate. It may not accurately reflect glucose control for 2-3 months. By everyone’s estimation, under 5.5% is normal, while over 6.5% is frank type 2 diabetes. It’s what goes on in between that’s up for grabs and it’s in this grey zone where most adults live. The higher it is, the greater the glycemic excursions, and the more risk for metabolic disease.
Insulin
Insulin is the hormone that helps shuttle glucose into cells (among many other things). Fasting Insulin is a measure of insulin levels unaffected by a recent meal and evaluates insulin production by the beta cells in the pancreas. It helps figure out the cause of abnormal blood glucose and to helps identify insulin resistance.
The body will do everything it can to maintain a fasting serum glucose below 100 mg/dL, including increasing insulin (that’s insulin resistance!). So, irrespective of fasting glucose, you want to have a simultaneous fasting insulin level, which tells you how hard the pancreas is working. Fasting insulin is an extremely important test because fasting insulin rises long before fasting glucose does, so maybe an early warning sign for metabolic disease. Optimal levels of fasting insulin are probably somewhere between ~2-6 uIU/mL.
High-Sensitivity C-Reactive Protein (hs-CRP)
It is a protein made by the liver that rises in blood concentration when you have inflammation. Inflammation is a key driver of metabolic dysfunction, and metabolic dysfunction leads to further inflammation. hsCRP can give you a signal of how much general inflammation is going on in the body. This test is used in conjunction with other tests, like lipid panel, to assess heart disease risk. The optimal range is usually less than 1.0 mg/L. The lower, the better.
Testing for inflammation: Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP)
These tests detect the presence of inflammation anywhere in the body and monitor its treatment.
Tests for ‘“thinning of blood”: PT, PTT, and INR
These tests, known collectively as a coagulation panel, look at the ability of your blood to clot. Disordered clotting ability can cause problems in surgery, during which bleeding is often expected. This test may also be used to monitor blood-thinning medications, such as Coumadin (warfarin).
Urinalysis
A urinalysis is a urine test to detect and manage a wide range of disorders, such as urinary tract infections, kidney disease, and diabetes. For example, a urinary tract infection can make urine look cloudy instead of clear. Increased levels of protein in urine can be a sign of kidney disease. Unusual urinalysis results often require more testing to uncover the source of the problem.
Urine microalbumin creatinine ratio
This test is used to screen for kidney disease. It can detect small amounts of albumin that escape from the blood through the kidneys into the urine several years before significant kidney damage becomes apparent.
Bottomline
A normal result does not promise health and an abnormal result does not mean you are sick. While it is helpful to have a general understanding of lab results and what they mean, your healthcare provider has training, knowledge, and experience to help figure out what significance they have on your health and wellbeing. The lab tests are complex, they represent inter-related systems in your body, and they’re worth investing time to understand. Medicine is an art and science shaded gray. There are very few absolutes, black and white. Interpreting lab results is a skill that is honed over the years, so don't feel a need to understand every nuance of your lab results. With your newly acquired awareness of the terms and objectives of your blood test, you can become a more active participant in your healthcare and a better custodian of your body.
References:
Published 1/10/2021
Updated 10/26/2021
About Us
Dr. Amar Singh, MD, and Dr. Poonam Singh, MD, are board-certified by the American Board of Internal Medicine and American Board of Obesity Medicine. They specialize in preventing, treating, and reversing chronic diseases using an evidence-based holistic approach. They are specifically interested in weight management, hormone re-balancing, and longevity. The American College of Physicians has recognized them as Fellows, FACP, for their excellence and contributions to medicine and the broader community. They enjoy teaching, volunteering, and advocating for their patients. Their mission is to share simple, effective, and proven strategies that lead to meaningful, sustainable, and long-lasting well-being.
