[This is the first of a 2-part article on how to interpret a standard complete blood test.]
Have you ever examined a printout of the results from a blood test? Unless you have a chemistry degree, a lot of the content there makes for a dry – and incomprehensible – read.
However, understanding what blood tests measure and how your numbers stack up can help you manage your wellness program better. Are you high in glucose (sugar) or low in calcium? Knowing the answers to questions such as these stacks the deck for your good health.
I just got back the results from my annual Comprehensive Metabolic Panel, and it’s all good, thank you very much. Following are the key substances present in human blood reported on my complete blood assay (test for levels).
Standard range: 74-106 mg/dL (milligrams per deciliter – 1/10 liter)
Glucose is a sugar present in the bloodstream. High levels may signal diabetes or prediabetes. The body converts carbohydrates from fruits and grains we eat and converts them into glucose, one of the body’s main energy sources.
Standard range: 7-21 mg/dL
BUN stands for Blood Urea Nitrogen and tests for kidney and liver health. The liver secretes urea as a waste product, which contains nitrogen:
“Urea and urea nitrogen are referred to somewhat interchangeably because urea contains nitrogen and because urea/urea nitrogen is the ‘transport method’ used by the body to rid itself of excess nitrogen.
Urea is released by the liver into the blood and is carried to the kidneys, where it is filtered out of the blood and released into the urine. Since this is an ongoing process, there is usually a small but stable amount of urea nitrogen in the blood.”
Urea levels rise when the kidneys or liver are having trouble getting rid of bodily waste. However, BUN concentrations may go down from liver damage or disease.
Standard range: 0.50-1.30 mg/dL
Creatinine is another bodily waste product, this time from the normal breakdown of muscle tissue. The kidneys process creatine as the body makes it and removes it with urine, so creatinine levels measure kidney function. The ability of the kidneys to process creatinine is called the creatinine clearance rate (CCR).
- eGFR MDRD
Standard range: >60 mL/min/1.73m2 (milliliters per minute per square meter)
Creatinine CCR (clearance rate – see the section above), age, body size, and gender are all used to calculate the estimated glomerular filtration rate – eGFR. This test is deemed the best for sizing up the health of the kidneys. Doctors use it to gauge the stage of a patient’s kidney disease or the effectiveness of dialysis treatments.
“A eGFR below 60 for three months or more or a eGFR above 60 with kidney damage (marked by high levels of albumin in your urine) indicates chronic kidney disease,” according to the National Kidney Foundation.
MDRD stands for Modification of Diet in Renal Disease. A study group with this name formulated a way to measure kidney health in Caucasian and Negro ethnic groups.
The MDRD Study equation “has been validated extensively in Caucasian and African American populations between the ages of 18 and 70 with impaired kidney function…and has shown good performance for patients with all common causes of kidney disease.”
Standard range: 136-145 mmol/L (millimoles – one-thousandth of a mole, which is 6 followed by 23 zeros – per liter)
This test is also called a serum sodium test. Sodium (Na+) is an electrolyte, which is an electrically charged mineral. A level of blood sodium within normal limits (WNL) is essential for good health, particularly nerve and muscle function.
We get sodium from food and beverages. The body then eliminates it and other electrolytes through urine, perspiration, and stool.
High levels of blood sodium are linked with increased blood pressure, while low levels may show up as nausea, vomiting, exhaustion, or dizziness.
Standard range: 3.5-5.1 mmol/L
Chloride is another important electrolyte. Chloride, sodium, and potassium (also an electrolyte) help balance the body’s pH levels (acids and bases). In addition, chloride aids the movement of fluid in and out of the cells.
A high level of chloride in the blood is a common sign that the kidneys are malfunctioning. A low chloride level may be indicated by becoming ill and dehydrated.
Standard range: 22-31 mmol/L
This test measures the amount of carbon dioxide (CO2) in the blood serum (the liquid part of blood). It has many names: carbon dioxide test, TCO2 test, total CO2 test, bicarbonate test, HCO3 test, and CO2 test-serum.
An imbalance between the oxygen and carbon dioxide in your blood or a pH imbalance in your blood may reveal problems with the kidneys, metabolism, or the respiratory system.
Watch for the second part of this 2-part article on how to interpret a standard complete blood test!]