Medical Check Ups

Renal Function Testing and Diagnostic Methods

Q: What is the kidney function index?

Kidney function can be reflected by the levels of creatinine and urea in the blood. Elevated levels indicate a decline in the function of both kidneys. If serum creatinine reaches 140 umol/L (1.6 mg/dl), it means the kidney function has declined by 50%.

Q: How can I determine if I have chronic kidney disease from the kidney function index?

Chronic kidney failure can be divided into the following four stages. When kidney function falls below 25% of normal, uremia appears, leading to kidney failure. 階段 腎功能指數 Renal Insufficiency 51% – 80% of normal renal function Renal Impairment 25% – 50% of normal renal function Renal Failure 15% – 25% of normal renal function Late-stage Renal Failure 10-15% of normal renal function

Q: Can these tests be performed together?

Since the symptoms of kidney disease and renal failure are not apparent, multiple tests are often required for a clear diagnosis of kidney function. Therefore, the aforementioned tests can be performed together, and conducting different tests can help doctors identify signs of kidney dysfunction.

One of the functions of the kidneys is detoxification, where they recycle useful substances and eliminate toxins, uric acid, and nitrogenous waste through the production of urine. When renal function weakens, the body is unable to eliminate excess fluids and waste, eventually leading to kidney failure. But what exactly is renal function? What does the level of renal function indicate? How much does renal function testing cost at different healthcare institutions? The Bowtie team has gathered relevant information on renal function to provide a detailed understanding of renal function testing. Let's explore the details of renal function testing together! When should you consider getting tested?

Author Bowtie Team

Date 2023-07-12

Updated on 2023-09-12

When should you consider getting tested?Who is at higher risk and should consider testing?Kidney function self-assessment Methods of kidney function testing and common diagnostic indicators Cost of Renal Function Tests:FAQ

When should you consider getting tested?

If any of the following symptoms occur, it could be a warning sign of kidney problems. It is important to seek medical attention immediately and undergo a series of detailed tests to identify the underlying cause.

Burning sensation during urination
Increased frequency of urination
Presence of blood in the urine
Swelling in the lower extremities
Swelling around the eyes and face, accompanied by back pain
High blood pressure

Who is at higher risk and should consider testing?

If you have any of the following factors, it may increase your risk of developing chronic kidney disease. It is advisable to consult a doctor and undergo regular testing:

Advanced age (40 years or older)
Long-term smoking
Family history of kidney disease
Structural abnormalities of the kidneys
Regular exposure to cadmium, trichloroethylene, asbestos, or petroleum due to occupational reasons
Obesity (BMI > 30)
Regular use of medications that may harm the kidneys
Diabetes
High blood pressure
Heart (cardiovascular) disease
Regular use of over-the-counter or pain medications
African-American, Native American, or Asian-American ethnicity

Kidney function self-assessment

If you suspect kidney problems, you can self-assess whether you have the following symptoms:

Self-assessment method	Symptoms
Do you have swelling?	Pay attention if you have swelling within two weeks after catching a cold Wrinkles on the face disappear Depression of subcutaneous tissue (pressing the part of the lower leg bone with a finger, it takes a while to recover!)
Are there any abnormal urine characteristics?	Frequent urination Decreased urination Nocturia (excessive urination at night) Polyuria (excessive urination) Abnormal urine color Presence of blood in the urine
Do you experience back or loin pain?	Pain in the back, loin, or lower abdomen Heaviness in the waist
Do you experience fatigue or headaches?	Fatigue Headaches General weakness
Does your complexion look unhealthy?	Pale complexion Darkening of the forehead Darkening of the skin
Do you have difficulty seeing nearby objects?	Visual impairment Difficulty reading

However, self-assessment may not be accurate. If you suspect kidney function problems, it is important to seek professional advice from a doctor.

Methods of kidney function testing and common diagnostic indicators

Early-stage chronic kidney disease may not present any symptoms, and problems can only be detected through testing. The following are 6 key indicators used to measure kidney function:

Indicator	Test	Normal Range
Creatinine	Creatinine is a waste product produced by muscles. Doctors compare the level of creatinine in a urine sample to that in the blood to assess how much waste the kidneys are filtering out	Female：Below 1.2 Male：Below 1.4
Blood Urea Nitrogen (BUN)	Urea nitrogen is a waste product in the body that is produced as proteins break down. An elevated level indicates that the kidneys are not effectively filtering out these waste products	7 – 20 mg
Glomerular Filtration Rate (GFR)	The rate at which blood is filtered by the kidneys.	Higher than 60
Urinary Protein	Excessive excretion of albumin in the urine indicates abnormal kidney function	90-120ml/min
Urinalysis Analysis	Analysis of urine sediments, including blood, pus, bacteria, glucose, and protein. Normal sediment should not be present. The presence of sediment indicates possible kidney or bladder infection, kidney disease, kidney stones, or diabetes.	Normal sediment should not be present. The presence of sediment indicates possible kidney or bladder infection, kidney disease, kidney stones, or diabetes.
Blood Pressure	Measurement of the pressure exerted on the blood vessels during heart function.	<140/90 mmHg

In addition to these indicators, doctors may perform other tests to accurately assess a patient’s kidney function. The following are common diagnostic procedures:

Blood Test

Principle:

Assess the overall health condition of a patient by extracting blood samples. This test ensures the safety of patients with renal cancer, as it helps evaluate their anemia levels and reduces the risk associated with various treatments.

Purpose:

The main parameters examined in a blood test are urea nitrogen and creatinine (normal range: 0.7~1.4 mg/dl). Higher values indicate poorer kidney function.

Suitable Individuals or Cases:

Not recommended for individuals who have recently undergone physical therapy.

Urinalysis

Principle:

Extract urine samples from patients and send them to the laboratory for analysis.

Purpose:

The goal is to detect the presence of “proteinuria.” In healthy adults, the daily protein excretion in urine should be ≤150 mg.

Renal Ultrasound Scan

Principle:

Uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs.

Purpose:

The aim is to detect structural issues in the kidneys, measure kidney size, identify kidney stones or tumors, and assess for enlargement or shrinkage of the kidneys.

Intravenous Pyelography :

Principle:

An X-ray examination of the urinary tract that involves injecting a contrast agent to visualize the kidneys, bladder, and the tubes (ureters) that transport urine from the kidneys to the bladder.

Purpose:

Used to diagnose potential urinary tract conditions such as kidney stones, bladder stones, enlarged prostate, renal cysts, or urinary tract tumors.

Suitable Individuals or Cases:

Some individuals may experience side effects from the injection of X-ray contrast agents. Pregnant women should inform their doctors about their pregnancy.

Renal Biopsy

Principle:

An invasive procedure where a needle is inserted into the kidney to extract a small tissue sample.

Purpose:

Assists in disease diagnosis, guides medication treatment, and determines prognosis. Helps understand the severity of kidney disease.

Suitable Individuals or Cases:

When the aforementioned imaging tests are not clear enough for surgery, doctors may consider a biopsy for live tissue examination.

Cost of Renal Function Tests:

The following table lists the prices of common renal function tests at four private hospitals. The diagnostic services provided by each hospital may not be identical. Factors such as room type, inclusion of contrast agents, etc., can also affect the prices. For accurate and detailed pricing, it is recommended to directly inquire with the hospitals.

Private Hospital	Examination Item	Fees
Hong Kong Sanatorium & Hospital	Union Hospital Renal Function Test (urea/creatinine/sodium/potassium/chloride/bicarbonate)	HK$140 起（per examination item）
	Urinalysis	Starting from HK$190
	Ultrasound Scan (Kidneys and Bladder)	Starting from HK$3,820
	Cystoscopy	Starting from HK$23,067
Gleneagles Hong Kong Hospital	Renal Function Test	Starting from HK$640
	Urinalysis	Starting from HK$160
	Ultrasound Scan (Kidneys and Bladder)	Starting from HK$1,590
	Voiding Cystourethrogram	Starting from HK$4,410
	Cystoscopy +/- Biopsy	Starting from HK$21,133
Saint Teresa’s Hospital	Renal Function (urea, creatinine, total protein, albumin, albumin-to-globulin ratio, sodium, potassium, chloride, bicarbonate)	Starting from HK$630
	Urinalysis	Starting from $155
	Cystoscopy	Starting from HK$2,700
	Ultrasound Scan (Kidneys)	Starting from HK$1,000
Hong Kong Baptist Hospital	Blood Test	Starting from HK$420
	Urinalysis	Starting from HK$180
	Ultrasound Scan (Kidneys)	Starting from HK$1,040

NoteThe above price information is for reference only (updated as of February 3, 2023).

FAQ

What is the kidney function index?

Kidney function can be reflected by the levels of creatinine and urea in the blood. Elevated levels indicate a decline in the function of both kidneys. If serum creatinine reaches 140 umol/L (1.6 mg/dl), it means the kidney function has declined by 50%.

How can I determine if I have chronic kidney disease from the kidney function index?

Chronic kidney failure can be divided into the following four stages. When kidney function falls below 25% of normal, uremia appears, leading to kidney failure.

階段	腎功能指數
Renal Insufficiency	51% – 80% of normal renal function
Renal Impairment	25% – 50% of normal renal function
Renal Failure	15% – 25% of normal renal function
Late-stage Renal Failure	10-15% of normal renal function

Can these tests be performed together?

Since the symptoms of kidney disease and renal failure are not apparent, multiple tests are often required for a clear diagnosis of kidney function. Therefore, the aforementioned tests can be performed together, and conducting different tests can help doctors identify signs of kidney dysfunction.

Source

這篇文章有用嗎？

Author

Bowtie Team

The Bowtie Life Insurance Company Limited is an authorized life insurance company and Hong Kong’s very first virtual insurer approved. Through the use of modern technology and medical expertise, Bowtie offers an agent-free, commission-free and more convenient online platform for customers to quote, apply and claim for Voluntary Health Insurance Scheme (VHIS) anytime anywhere. Bowtie is ranked first in the direct channel sales throughout 2021.

Stay up to date at www.bowtie.com.hk