One of our most common patient portal questions
“You’re the first person to explain it to me, now it makes sense” or some variation of that phrase is something Tiffany & I hear too often from our patients. Especially when we are working in the hospital – when patients are feeling the most confused and anxious. It’s one of the main reasons we love what we do. Providing clear education allows us to make a real difference for patients – it helps patients take back some control when facing the unknown.
When patient portals became available and patients gained almost instant access to their lab results, often before their provider had a chance to review them – anxiety rose. With more information came more confusion, understandably so. Many patient portal messages that we answer are questions about flagged lab abnormalities. Often, these labs aren’t truly concerning or can be easily explained.
So, let us explain…
Your CBC, or Complete Blood Count, is a lab report of 9 values, not including a differential (we can talk about that another time):
Honestly, there’s almost always a couple abnormal values, but they may not mean anything or can be easily explained.
If you’re a little dehydrated, a little too hydrated, or coming down with a mild illness, you can see small changes in the results. It’s natural for your labs to fluctuate, especially if you’re having it checked frequently/closely together. Always speak to your doctor if something doesn’t seem right, but we hope this post helps ease some anxiety.
Your white blood cell (WBC) count is essentially your immune system. If it’s high, that usually indicates infection or inflammation. If it’s low, you may have a nutritional deficiency or viral illness. In some cases, it can mean something more serious. A low WBC or severely high WBC deserves a deeper investigation for underlying conditions.
Next up is the red blood cell (RBC) count. Your RBCs have hemoglobin inside them, but they are not the same thing. When RBCs are elevated, your blood is thicker than usual, which increases risk of a blood clot. This value can be high due to cigarette smoking, sleep apnea, dehydration, or testosterone use. A low RBC value could mean many things, ranging from benign issues to blood disorders. Many other results need to be considered along with it to make a determination.
Hemoglobin (HGB) and hematocrit (HCT) are very interconnected. HGB is a protein packed with iron and its inside of each of your red blood cells. Oxygen attaches to your HGB and your red blood cells take it where it needs to go!
Rather than a cell or protein, HCT is a calculation – a percentage. It tells you how much of your blood is made of red blood cells compared to how much of it is liquid (called plasma). When HGB is low, you have fewer and smaller red blood cells, so naturally you have a lower HCT too. The reverse is also true – a high HGB will cause a high HCT. Low hemoglobin often indicates a nutritional deficiency, but could also mean you are bleeding, have chronic illness – like kidney disease, or more rarely – cancer. When your HGB is elevated, it could indicate the same things as a high red blood cell count: cigarette smoking, sleep apnea, dehydration, or testosterone use.
MCV, or mean cell volume, can tell you a lot! It is a measure of the size of your red blood cells. A high MCV = a large red blood cell, a low MCV = a small red blood cell. Most commonly, changes in cell size are due to a nutritional deficiency, but a large cell (high MCV) can sometimes indicate a blood disorder. It always deserves a thorough evaluation.
Up next is the color of your red blood cells – the MCH and MCHC. MCH stands for mean corpuscular hemoglobin. It tells us the average amount of hemoglobin each red blood cell is carrying. MCHC, or mean corpuscular hemoglobin concentration, compares that average amount of hemoglobin (MCH) to the size of the red blood cell (remember – that is the MCV!). This tells us how full the red blood cell is, not just how much it’s carrying. When MCHC is low, your red blood cells are not very full, so they can look paler/lighter red under a microscope. Commonly, a low MCH or MCHC is the result of not having enough iron.
RDW is the red blood cell distribution width, which tells you how much your red blood cells differ in size from each other. Typically, they’re all pretty similar in size, but when something starts brewing in your blood, we can see the RDW increase – meaning your red blood cells may be starting to become larger or smaller for some reason. Picture an egg carton. Normally, the eggs are pretty close in size to each other – that’s a normal RDW, but if the egg carton had a mix of small, medium and large eggs, that’s a high RDW. When your RDW is high, that could mean you are developing anemia (a low hemoglobin).
The last piece of your CBC is platelets. Platelets help slow bleeding and form clots. When they are high, you can clot more easily and when they are low, you can bleed more easily. If your platelets are high, it could be reactive – meaning they are responding to something else going on your body, such as infection, inflammation, or iron deficiency. In rare cases, it could point to a blood disorder. Low platelets can be seen in nutritional deficiencies, significant bleeding, liver disease, spleen dysfunction, viral illness, severe illness (like bacteria in the blood requiring hospitalization), or more rarely – cancer or autoimmune disease.
Take a look at your last CBC and see if you can understand what the numbers are telling you!
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