Complete Guide to Reading Health Checkup Results - Understanding Every Number and Warning Sign

Introduction: Understanding the Numbers Behind Your Health

Many of us get annual health checkups, but when we receive our results, the dense rows of numbers and medical jargon can feel overwhelming. After a brief explanation from the doctor, we often leave without truly understanding what is happening inside our bodies. A health checkup report is not just a piece of paper - it is a report that translates the signals from your body into numbers.

However, there is one critical point to keep in mind: Falling outside the normal range does not automatically mean you have a disease. Various factors such as your condition on the day of the test, what you ate the night before, stress, and medications can affect test results. Conversely, even if your values fall within normal range, you should pay attention if they are near the borderline. What matters most is interpreting the results in their overall context, rather than focusing on a single number.

This article provides a thorough explanation of each major item included in health checkup results. From basic body measurements to blood glucose, cholesterol, liver function, kidney function, anemia, thyroid, urinalysis, and tumor markers - we have organized the normal values, what abnormalities mean, and when additional testing is needed with clear reference tables. Keep this guide alongside your health checkup report for a deeper understanding of your health status.

1. Basic Body Measurements and Blood Pressure

The first step of a health checkup is basic body measurements. Height, weight, waist circumference, and blood pressure measurements are the simplest yet most important indicators for assessing your overall health status.

1.1 BMI (Body Mass Index)

BMI (Body Mass Index) is calculated by dividing your weight (kg) by the square of your height (m). For example, a person who is 170 cm tall and weighs 70 kg has a BMI of 70 / (1.7 x 1.7) = 24.2. The BMI classification applied to Asians, based on the Korean Society for the Study of Obesity criteria, is as follows:

Classification	BMI Range (kg/m2)	Health Risk
Underweight	Below 18.5	Risk of nutritional deficiency, weakened immunity
Normal	18.5 - 22.9	Low
Overweight (Pre-obese)	23.0 - 24.9	Slightly increased
Obesity Class I	25.0 - 29.9	Moderately increased
Obesity Class II	30.0 - 34.9	High
Obesity Class III (Severe Obesity)	35.0 and above	Very high

1.2 Blood Pressure

Blood pressure is expressed as two values: systolic blood pressure (the pressure when the heart contracts) and diastolic blood pressure (the pressure when the heart relaxes). For example, 120/80 mmHg means a systolic pressure of 120 and a diastolic pressure of 80.

Classification	Systolic (mmHg)	Diastolic (mmHg)	Action
Normal Blood Pressure	Below 120	Below 80	Maintain
Elevated Blood Pressure	120 - 129	Below 80	Lifestyle modifications
Prehypertension	130 - 139	80 - 89	Active lifestyle modifications, regular monitoring
Hypertension Stage 1	140 - 159	90 - 99	Physician consultation, consider medication
Hypertension Stage 2	160 and above	100 and above	Immediate physician consultation, medication

White Coat Hypertension is a phenomenon where blood pressure readings are elevated only when measured at a hospital or screening facility. It is caused by nervousness and stress, and studies suggest that approximately 15-30% of all hypertension diagnoses fall into this category. If suspected, you can obtain a more accurate blood pressure reading by measuring at home with an automatic blood pressure monitor - twice in the morning after waking and twice in the evening before bed - and recording the average over 7 days.

1.3 Waist Circumference

Waist circumference is an indicator that indirectly reflects the degree of visceral fat accumulation. The abdominal obesity criteria based on the Korean Society for the Study of Obesity standards are as follows:

Sex	Abdominal Obesity Threshold	Associated Risks
Male	90 cm (approx. 35 inches) or more	Metabolic syndrome, cardiovascular disease, type 2 diabetes
Female	85 cm (approx. 33 inches) or more	Metabolic syndrome, cardiovascular disease, type 2 diabetes

Visceral fat is metabolically far more active than subcutaneous fat, promoting insulin resistance, chronic inflammation, and dyslipidemia. Even if your BMI is normal, exceeding the waist circumference threshold increases health risks, so it is essential to check both measurements together.

2. Blood Tests - Blood Glucose

Blood glucose tests are a core component for diagnosing and managing diabetes. Health checkups primarily measure two values: fasting blood glucose and glycated hemoglobin (HbA1c).

2.1 Fasting Blood Glucose

Fasting blood glucose is the concentration of glucose in the blood measured after a minimum of 8 hours of fasting. It is the most fundamental indicator for diabetes diagnosis, and the standards are as follows:

Classification	Fasting Blood Glucose (mg/dL)	Significance and Action
Normal	Below 100	Normal range, maintain annual checkups
Impaired Fasting Glucose (Prediabetes)	100 - 125	Prediabetic stage, dietary control and exercise needed
Suspected Diabetes	126 and above	Re-testing needed, meets diabetes diagnostic criteria

If your fasting blood glucose falls in the 100-125 mg/dL range classified as "impaired fasting glucose," there is a high risk of progressing to diabetes. At this stage, lifestyle modifications such as weight loss (5-7%), regular exercise (at least 150 minutes of moderate exercise per week), and limiting refined carbohydrate intake can prevent progression to diabetes. Meanwhile, postprandial blood glucose is measured 2 hours after a meal, with levels below 140 mg/dL considered normal. Since some people may have normal fasting glucose but elevated postprandial glucose ("postprandial hyperglycemia"), relying on fasting glucose alone is not sufficient.

2.2 Glycated Hemoglobin (HbA1c)

Glycated hemoglobin (HbA1c) represents the percentage of hemoglobin in red blood cells that has bonded with glucose. Since red blood cells have a lifespan of approximately 120 days, HbA1c reflects the average blood glucose level over the past 2-3 months. It is a more stable indicator than fasting blood glucose because it is unaffected by the day's meals or physical condition.

Classification	HbA1c (%)	Estimated Average Glucose (mg/dL)	Significance
Normal	Below 5.7%	Below approx. 117	Normal blood glucose control
Prediabetes	5.7% - 6.4%	Approx. 117 - 137	Diabetes risk group, active management needed
Diabetes	6.5% and above	Approx. 140 and above	Meets diabetes diagnostic criteria
Diabetes Control Target	6.5% - 7.0%	Approx. 140 - 154	Target range for most diabetes patients
Poorly Controlled	8.0% and above	Approx. 183 and above	Increased complication risk, treatment intensification needed

3. Blood Tests - Cholesterol (Lipid Panel)

The lipid panel measures blood fat components to assess cardiovascular disease risk. It comprehensively checks four items: total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides.

3.1 Total Cholesterol, LDL, HDL, and Triglycerides

LDL cholesterol accumulates on arterial walls and causes atherosclerosis, hence its nickname "bad cholesterol." HDL cholesterol removes cholesterol from arterial walls and transports it to the liver, earning it the name "good cholesterol." Triglycerides are a fat component that responds sensitively to carbohydrate and alcohol intake.

Test Item	Normal	Borderline	High (Risk)
Total Cholesterol (mg/dL)	Below 200	200 - 239	240 and above
LDL Cholesterol (mg/dL)	Below 130	130 - 159	160 and above
HDL Cholesterol (mg/dL)	60 and above (higher is better)	40 - 59	Below 40 (lower is riskier)
Triglycerides (mg/dL)	Below 150	150 - 199	200 and above

The LDL cholesterol target varies depending on individual cardiovascular risk. For patients with cardiovascular disease or diabetes, the target is below 100 mg/dL, and for high-risk individuals, below 70 mg/dL. When triglycerides are very high at 500 mg/dL or above, there is a risk of acute pancreatitis and immediate treatment is necessary.

Triglycerides are the lipid item most closely related to dietary habits. Excessive carbohydrate intake (rice, noodles, bread, fruit), alcohol consumption, and sugary beverages rapidly raise triglycerides. Conversely, omega-3 fatty acids (found in oily fish like mackerel and salmon), regular aerobic exercise, and weight loss are effective at reducing triglycerides.

4. Liver Function Tests

Liver function tests assess the degree of liver cell damage and the overall functional status of the liver. The liver is called the "silent organ" because symptoms often do not appear until significant damage has occurred, making regular testing extremely important.

4.1 AST (GOT) and ALT (GPT)

AST (Aspartate Aminotransferase, GOT) and ALT (Alanine Aminotransferase, GPT) are enzymes found inside liver cells. When liver cells are damaged, these enzymes leak into the bloodstream, causing elevated levels.

Test Item	Normal Range	Mild Elevation	Moderate or Higher Elevation
AST (GOT)	0 - 40 U/L	40 - 80 U/L	80 U/L and above
ALT (GPT)	0 - 40 U/L	40 - 80 U/L	80 U/L and above

ALT has higher liver specificity than AST. ALT is found primarily in the liver, while AST is also present in the heart, muscles, and kidneys. Therefore, if only ALT is elevated, liver disease should be suspected first. If only AST is elevated independently, other causes such as muscle damage or heart disease should also be considered.

• Mild elevation (40-80 U/L): Non-alcoholic fatty liver disease, light drinking, drug side effects, temporary elevation after intense exercise
• Moderate elevation (80-200 U/L): Steatohepatitis, chronic hepatitis (hepatitis B or C), alcoholic liver disease, drug-induced liver injury
• Severe elevation (200 U/L and above): Acute hepatitis, exposure to hepatotoxic substances, severe liver damage

4.2 Gamma-GT (GGT)

Gamma-GT (Gamma-Glutamyl Transferase, GGT) is an enzyme found in the liver and biliary system that is particularly sensitive to alcohol consumption.

Classification	Male (U/L)	Female (U/L)
Normal	11 - 63	8 - 35
Mild elevation	64 - 130	36 - 70
Moderate or higher elevation	130 and above	70 and above

Major causes of elevated gamma-GT include heavy drinking, alcoholic liver disease, gallstones/bile duct obstruction, medications (anticonvulsants, antibiotics, etc.), obesity, and fatty liver. When AST/ALT are normal but gamma-GT alone is elevated, habitual drinking should be suspected first. If the values normalize within 2-4 weeks after abstaining from alcohol, it confirms that alcohol was the cause.

4.3 Bilirubin and Albumin

Bilirubin is a yellow pigment produced when red blood cells break down, which is processed by the liver and excreted through bile. When liver function is impaired or the bile ducts are blocked, blood bilirubin levels rise, potentially causing jaundice (yellowing of the skin and whites of the eyes).

• Total bilirubin normal range: 0.1 - 1.2 mg/dL
• Direct bilirubin normal range: 0.0 - 0.4 mg/dL

Albumin is a protein synthesized by the liver that reflects the liver's synthetic function. The normal range is 3.5-5.2 g/dL. A decrease below 3.5 g/dL may suggest liver cirrhosis, severe nutritional deficiency, or chronic disease. Albumin is a long-term indicator of liver function, reflecting chronic rather than acute changes in liver function.

5. Kidney (Renal) Function Tests

The kidneys filter waste products from the blood, maintain fluid and electrolyte balance, and regulate blood pressure. The key items in kidney function testing are creatinine, BUN, and eGFR.

Test Item	Normal Range	Significance
Creatinine	Male: 0.7-1.3 mg/dL, Female: 0.6-1.1 mg/dL	Muscle metabolism byproduct, reflects kidney excretory function
BUN (Blood Urea Nitrogen)	7 - 20 mg/dL	Protein metabolism byproduct, reflects kidney function and dehydration
eGFR (Estimated Glomerular Filtration Rate)	90 mL/min/1.73m2 and above	Comprehensive indicator of kidney function (most important)

eGFR (Estimated Glomerular Filtration Rate) is a value calculated from creatinine, age, and sex that estimates the volume of blood the kidneys can filter per minute. It is the most important indicator used for staging chronic kidney disease (CKD).

CKD Stage	eGFR (mL/min/1.73m2)	Kidney Function Status	Action
Stage 1	90 and above	Normal or mildly decreased function	Manage underlying condition
Stage 2	60 - 89	Mildly decreased function	Prevent progression, manage risk factors
Stage 3a	45 - 59	Mild to moderately decreased function	Nephrology consultation recommended
Stage 3b	30 - 44	Moderate to severely decreased function	Complication management, specialized treatment
Stage 4	15 - 29	Severely decreased function	Prepare for dialysis/transplant
Stage 5	Below 15	End-stage renal failure	Dialysis or kidney transplant

6. Blood Tests - Anemia

Anemia-related tests evaluate the blood's oxygen-carrying capacity. The key indicators are hemoglobin, red blood cell count, and hematocrit.

Test Item	Male Normal	Female Normal	Anemia Criteria
Hemoglobin (Hb)	13.0 - 17.5 g/dL	12.0 - 16.0 g/dL	Male below 13.0, Female below 12.0
Red Blood Cell Count (RBC)	4.5 - 5.5 x 10^6/uL	4.0 - 5.0 x 10^6/uL	Below reference value suggests anemia
Hematocrit (Hct)	38.3% - 48.6%	35.5% - 44.9%	Below reference value suggests anemia

Treatment for anemia varies greatly depending on the cause, so a simple diagnosis of "anemia" is insufficient - identifying the underlying cause is crucial.

• Iron deficiency anemia: The most common type of anemia. In women of childbearing age, iron loss through menstruation is a primary cause. A low ferritin level (below 12 ng/mL) can confirm the diagnosis. Treatment involves iron supplements and dietary improvements (red meat, spinach, tofu, etc.).
• Vitamin B12/folate deficiency anemia: Also known as megaloblastic anemia, this can occur in vegetarians or after gastric surgery. It is characterized by an MCV (Mean Corpuscular Volume) above 100 fL.
• Anemia of chronic disease: Anemia accompanying chronic infections, autoimmune diseases, or malignancies. Treating the underlying condition takes priority.
• Aplastic anemia: A serious form of anemia where bone marrow function is reduced, decreasing blood cell production. Specialized treatment is required.

7. Thyroid Function Tests

The thyroid is a butterfly-shaped endocrine gland located at the front of the neck that secretes thyroid hormones regulating the body's metabolic rate. Health checkups primarily measure TSH and Free T4.

Test Item	Normal Range	When High	When Low
TSH (Thyroid-Stimulating Hormone)	0.27 - 4.2 mIU/L	Hypothyroidism suspected	Hyperthyroidism suspected
Free T4	0.93 - 1.70 ng/dL	Hyperthyroidism suspected	Hypothyroidism suspected

Hyperthyroidism is a condition of excessive thyroid hormone production, with symptoms including weight loss, increased heart rate, hand tremors, heat intolerance, and anxiety. The most common cause is Graves' disease (an autoimmune disorder).

Hypothyroidism is a condition of insufficient thyroid hormone, with symptoms including weight gain, fatigue, cold intolerance, constipation, dry skin, and depression. The most common cause is Hashimoto's thyroiditis (an autoimmune disorder).

When thyroid nodules are found on ultrasound, the vast majority (over 90%) are benign. However, if a nodule is 1 cm or larger or has suspicious ultrasound features, a Fine Needle Aspiration (FNA) biopsy is needed to determine whether it is malignant. Thyroid nodules are found in approximately 50% of adults, so there is no need for excessive worry, but regular follow-up monitoring is necessary.

8. Urinalysis

Urinalysis is a simple yet important test that provides various information about kidney, urinary tract, and metabolic abnormalities. The key items are urine protein, urine occult blood, and urine glucose.

Test Item	Normal	Significance When Abnormal
Urine Protein	Negative (-)	Kidney disease (glomerulonephritis, diabetic nephropathy), hypertensive kidney damage, urinary tract infection, temporary positive after intense exercise
Urine Occult Blood	Negative (-)	Urinary tract infection, kidney stones, glomerulonephritis, bladder/kidney cancer, menstrual contamination
Urine Glucose	Negative (-)	Diabetes (glucose appears in urine when blood glucose exceeds 180 mg/dL), renal tubular disorder

A positive (+) result in urinalysis does not necessarily indicate disease. Intense exercise, menstruation, and dehydration can temporarily produce positive results. However, if positive results persist on repeated testing, additional investigation is essential. In particular, persistent positive urine protein is a very important signal for early detection of kidney disease, and nephrology consultation is recommended.

9. Tumor Marker Tests

Tumor markers are substances produced by cancer cells or generated by the body in response to cancer. They are measured through blood tests, and the commonly included items in health checkups are as follows:

Tumor Marker	Normal Range	Associated Cancers	Non-Cancer Causes of Elevation
CEA (Carcinoembryonic Antigen)	5.0 ng/mL or below	Colorectal, gastric, lung, breast cancer	Smoking, inflammatory bowel disease, liver cirrhosis
AFP (Alpha-Fetoprotein)	10 ng/mL or below	Hepatocellular carcinoma (liver cancer)	Chronic hepatitis, liver cirrhosis, pregnancy
PSA (Prostate-Specific Antigen)	4.0 ng/mL or below	Prostate cancer	Benign prostatic hyperplasia, prostatitis, cycling
CA-125	35 U/mL or below	Ovarian cancer	Endometriosis, pelvic inflammatory disease, menstruation, pregnancy
CA 19-9	37 U/mL or below	Pancreatic, bile duct cancer	Gallstones, cholecystitis, chronic pancreatitis

The general course of action when tumor marker levels are elevated is as follows:

1. Re-test after 1-3 months to monitor trends in the values
2. If values continue to rise or exceed twice the normal level, perform related imaging studies (CT, MRI, ultrasound)
3. If imaging reveals abnormal findings, confirm with a biopsy
4. If non-cancer causes exist (smoking, chronic disease, etc.), manage the cause and re-test

10. Guide to Using Your Checkup Results

Here is how to effectively use your health checkup results.

What to Do When Abnormalities Are Found

• "Normal": Your current test results are within reference ranges, but you should continue regular checkups.
• "Borderline" or "Caution": Slightly outside the normal range; lifestyle modifications (diet, exercise, alcohol cessation, smoking cessation) are needed, and re-testing in 3-6 months is recommended.
• "Abnormal" or "Findings Present": Outside the normal range; consultation with a specialist in the relevant field is necessary. Additional detailed testing may be required.
• "Further Examination Required": You must visit a specialist for additional testing. Please do not delay.

When Re-Testing Is Recommended

Re-testing after a certain period is recommended in the following cases:

• When values are borderline and confirmation of whether temporary factors are involved is needed
• When adequate fasting before the test was not achieved (affects blood glucose and cholesterol)
• When intense exercise was performed on the day of the test (affects muscle enzymes and urine protein)
• During menstruation or while taking medications such as cold medicine
• When an abnormality appears for the first time and trend confirmation is needed

Lifestyle Improvement Checklist

Abnormal Item	Priority Improvement	Specific Actions
High blood pressure	Sodium restriction, exercise	Salt intake under 5g per day, walk 30 minutes daily
High blood glucose	Carbohydrate control, weight management	Reduce white rice intake, walk 15 minutes after meals
High cholesterol	Saturated fat restriction, fiber intake	Reduce greasy foods, eat at least 3 vegetable side dishes daily
Elevated liver enzymes	Alcohol cessation, weight management	At least 2 alcohol-free days per week, 5% weight loss if overweight
Anemia	Iron intake, identify cause	Red meat 2-3 times per week, take vitamin C concurrently

National Health Screening: Free Eligibility and Schedule

The National Health Insurance Service (NHIS) in South Korea provides the following national health screenings free of charge:

Screening Type	Eligibility	Frequency
General Health Screening	Regional household heads, workplace subscribers, dependents and household members aged 20+	Once every 2 years (annually for non-office workers)
Gastric Cancer Screening	Age 40 and above	Once every 2 years
Colorectal Cancer Screening	Age 50 and above	Once a year (fecal occult blood test)
Liver Cancer Screening	High-risk individuals aged 40+	Once every 6 months
Breast Cancer Screening	Women aged 40 and above	Once every 2 years
Cervical Cancer Screening	Women aged 20 and above	Once every 2 years
Lung Cancer Screening	Ages 54-74 with 30+ pack-year smoking history	Once every 2 years (low-dose CT)

Conclusion: Understanding Your Numbers Is Where Health Begins

Your health checkup report is a "health report card" that records your body's current status in numbers. Understanding these numbers makes it clear which areas need attention and which lifestyle habits need improvement. The table below summarizes the normal/caution/risk values for the key items covered in this guide at a glance.

Item	Normal	Caution (Borderline)	Risk (Abnormal)
BMI (kg/m2)	18.5 - 22.9	23.0 - 24.9	25.0 and above
Blood Pressure (mmHg)	Below 120/80	120-139 / 80-89	140/90 and above
Fasting Blood Glucose (mg/dL)	Below 100	100 - 125	126 and above
HbA1c (%)	Below 5.7	5.7 - 6.4	6.5 and above
Total Cholesterol (mg/dL)	Below 200	200 - 239	240 and above
LDL (mg/dL)	Below 130	130 - 159	160 and above
HDL (mg/dL)	60 and above	40 - 59	Below 40
Triglycerides (mg/dL)	Below 150	150 - 199	200 and above
AST/ALT (U/L)	0 - 40	41 - 80	80 and above
eGFR (mL/min)	90 and above	60 - 89	Below 60
Hemoglobin M/F (g/dL)	13.0+ / 12.0+	11.0-12.9 / 10.0-11.9	Below 11.0 / Below 10.0

Finally, health checkups are not something you do once and forget about - the key is to get them regularly, whether annually or periodically, to observe trends in your numbers. If a value that was normal last year has risen to borderline this year, even though it is not yet a disease, it is a signal to review your lifestyle habits. Conversely, if previously elevated values are improving through management, that is evidence you are heading in the right direction.

Understanding the numbers in your health checkup results is the very first and most important step in protecting your health. We hope this guide helps you read, understand, and take action based on your health checkup results. Recording your screening numbers in a smartphone health management app (Samsung Health, Apple Health, etc.) is very useful for tracking year-over-year changes at a glance. Knowing your numbers - that is where health begins.