The Impact of Natural 24-hour Fluctuations on Blood Test Results

Hey! 

You might be surprised to know that the body's natural 24-hour fluctuations can affect different types of tests.

Daily variations are known as circadian rhythms and can impact hormone levels, metabolism, and even blood composition, leading to potential discrepancies in test readings. 

Want to know more? 

Today’s article provides comprehensive information about how the body’s natural fluctuations affect several blood tests and what precautions you can take to receive accurate results. 

Understanding Circadian Rhythms and Blood Test Visibility 

Circadian rhythms pinpoint the body’s internal clock, regulating physical, mental, and behavioral changes over 24 hours. These rhythms affect several bodily functions, including metabolic activities, sleep-wake patterns, and hormone production. Biomarkers covered in blood tests show significant daily fluctuations, including stress levels, meal timing, and physical activity. 

The Impact of Natural 24-Hour Fluctuations on Blood Tests

Blood tests help diagnose and monitor various health conditions. A diurnal (24-hour) variation can affect several types of blood tests and increase the chance of receiving abnormal results. Below are some of the most commonly affected tests: 

1. Hormone Tests

Getting a hormone test done incorrectly can affect your test results. It can also make it difficult for a healthcare professional to diagnose the condition accurately. This is because hormone levels fluctuate throughout the day, leading to misleading results. 

Also read: Hormone Analysis for Women: Tests, Importance & Results

3 Different Types of Hormones:

• Cortisol

It is a stress hormone that peaks in the early morning and declines throughout the day. If you get your cortisol levels tested in the evening, it may show lower-than-normal values. This may mean you have Addison’s disease or secondary adrenal insufficiency. 

• Testosterone

Testosterone is a sex hormone. Males have 10 to 20 times higher values than females. The internal 24-hour clock, known as the circadian clock, regulates testosterone. Testosterone levels are typically highest in the morning and decrease as the day progresses. 

Additionally, if you are under 30, the decline in testosterone gets smaller, meaning you might see a 30% drop between morning and evening readings. If you are over 60, this decline is less than 10%. 

Consequently, for accurate results, testosterone tests are typically recommended in the early morning. 

• Thyroid-stimulating hormones (TSH)

Thyroid-stimulating hormones (TSH) are a crucial biomarker for diagnosing and monitoring thyroid conditions. TSH varies throughout the day, with a peak typically occurring between 11:00 p.m. and 5:00 a.m. and a nadir between 5:00 p.m. and 8:00 p.m., which is late afternoon or early evening. 

2. Blood Glucose Levels 

Blood glucose levels also fluctuate depending on several factors. These usually include the time of day, meal consumption, and insulin response. 

3 Different Types of Blood Glucose Test Include:

• Fasting Blood Glucose: 

Fasting blood sugar levels are measured in the morning, typically several hours after eating, to improve the accuracy of glucose levels. Researchers believe there can be a spike in blood sugar in the morning after fasting all night. This is due to the overnight release of certain hormones that increase insulin resistance. 

Also read: What a Fasting Blood Glucose Test Reveals About Your Health?

• Postprandial Glucose

This blood sugar test is performed after eating meals, typically two hours after eating. Postprandial glucose is significantly influenced by the time of testing and dietary choices. 

• HbA1C

HbA1C is not affected by daily fluctuations. It checks your average blood sugar over the past three months. 

3. Lipid Profile (Cholesterol and Triglycerides) 

Experts say that the time of day and meal size affect lipid levels. 

2 Important Components of Lipid Profile: 

Cholesterol

While total cholesterol levels do not fluctuate significantly, good cholesterol (HDL) and bad cholesterol may vary slightly due to dietary intake and metabolic processes. 

Triglycerides

Healthcare providers suggest fasting before a test for triglyceride levels to improve the accuracy of test results. This is because their levels tend to rise after eating and are highest in the evening. 

4. Iron and Ferritin Levels

Serum iron levels show fluctuations throughout the day. A diet influences them. 

Serum Iron Levels

Serum iron levels are regulated by the circadian rhythm. For adults and children, they peak late in the morning from 11:00 to 12:00, and they decline in the afternoon and evening. 

Women are 50% more likely to get a "low" serum iron result (< 10 umol/L) when tested in the early afternoon than in the morning. Male users get a higher percentage of "high" serum iron results (> 30 umol/L) than females (18.6% for males versus 10.3% for females), and the occurrence of "high" results decreases significantly after midday.

Ferritin

Ferritin is a marker of iron storage. It is relatively stable, but ferritin levels can be higher than normal due to inflammation and daily rhythms. 

5. Kidney Function Test (Creat

Kidney function test (KFT) can show mild variations based on hydration levels and time of the day. 

2 Important Indicators: 

Creatinine:

Creatinine levels are slightly lower in the morning than in the evening. This is most likely due to muscle activity and dietary intake during the day. 

Urea:

Urea levels can fluctuate depending on hydration levels and protein intake, necessitating standardized testing conditions. 

5 Factors That Can Impact Blood Test Fluctuations

Blood test fluctuations can be caused by several factors, including: 

1. Time of day: Time of day does matter, as many blood components peak in the morning and decrease later in the day. 
2. Fasting vs. nonfasting: Whether you are taking a test while fasting or without fasting makes a difference. Consequently, eating food before the test can cause fluctuations in glucose, lipid, and metabolic markers. 
3. Physical activity: Physical activity and exercise can increase muscle enzyme levels and affect plasma lipids, especially triglycerides. 
4. Hydration Status: Dehydration can affect your blood test results. Ensure you stay hydrated before the test to avoid spikes in blood sugar levels and other fluctuations in the blood test. 
5. Stress and sleep pattern: Poor sleep patterns and stress can elevate cortisol levels. Thus affecting the findings of blood tests. 

5 Best Practices that Can Ensure Accurate Blood Test Results

Following these practices can help minimize discrepancies due to natural fluctuations: 

• Schedule blood test in the morning: Fasting overnight and morning testing ensure more accurate baseline readings. 
• Follow fasting requirements: Avoid consuming regular meals and beverages for 8-12 hours before the test. Also, do not eat non-vegetarian food and drink alcoholic beverages to help improve the accuracy of your test results. 
• Stay hydrated: drinking enough water makes the blood draw smoother and results more reliable. 
• Avoid strenuous exercise: Avoiding strenuous exercise before going for a test can prevent temporary fluctuations in blood sugar, enzymes, and hormone levels. 
• Maintain consistency: Getting tested at the same time of day, under similar conditions, can help track accurate trends over time.

Redcliffe Labs: One-Stop Destination for Blood Tests

Natural 24-hour fluctuations can greatly impact blood test results, resulting in variability in diagnostic interpretations. These biomarkers clearly show that huge differences can be seen depending on the time of day a sample is collected. Taking a test in the morning can help maintain the highest consistency in test results. 

Healthy India Ki Trusted Lab—Redcliffe Labs is a one-stop destination for a wide range of blood tests for several purposes. Routine check-ups, specialized screenings, and genetic testing are available at affordable pricing with a home sample collection. Our lab experts use cutting-edge technology, ensuring precise and reliable test results, and expert pathology services help you understand your test results. 

Call us directly or download a Redcliffe Labs mobile app to book a blood test online. We are committed to quality, customer satisfaction, and making healthcare accessible and efficient. 

Step-by-step information on booking a test online from Redcliffe Labs. 

1. Visit the official Redcliffe Labs website: https://redcliffelabs.com/.
2. Browse or search for the specific test you need. 
3. Add the test to the cart. 
4. Complete the payment process online.

Note: You will receive confirmation through SMS and WhatsApp.

FAQs: 

1. Can blood test results change throughout the day?

Yes. Many biomarkers, such as cortisol, glucose, and iron levels, follow a natural circadian rhythm and fluctuate. 

2. Which blood tests are most impacted by daily fluctuations?

Blood tests for hormones, blood sugar, cholesterol, and iron levels are mostly affected by daily fluctuations. 

3. Why is getting a blood test done in the morning highly recommended?

Morning testing is highly recommended because it provides more standardized results, especially when fasting is needed for blood sugar and thyroid tests. 

4. Can stress and sleep bring fluctuations in blood test results?

Yes, poor sleep patterns and stress can fluctuate blood test results. They can also alter hormone levels, such as cortisol and adrenaline, impacting test accuracy. 

5. How can you minimize fluctuations in my test results?

Follow fasting guidelines, stay hydrated, schedule a test in the morning, avoid strenuous exercise before the test, and maintain consistent testing times for accurate comparisons.