Medical laboratory formulas and Basic calculations play a crucial role in the field of clinical laboratory testing. These calculations are utilized to interpret and analyze laboratory results, determine diagnostic parameters, assess organ function, and guide patient management. They enable healthcare professionals to derive meaningful insights from test data and make informed decisions.

Urine Protein Formula:

The test for protein in the urine measures the amount of albumin in your urine, compared to the amount of creatinine in your urine. This is called the urine albumin-to-creatinine ratio (UACR).

24 Hours Urine		0.04 – 0.12 g/24 hrs
Spot Urine	Result (mg/dl)	Up to 12.0 mg/dl

Urine Creatinine Formula:

A creatinine urine test measures the amount of creatinine in your urine. Creatinine is a chemical waste product produced by muscle metabolism. When your kidneys are functioning normally.

24 Hours Urine		0.5 -1.5 g/24 hrs
Spot Urine	Result (mg/dl)	60 – 166 mg/dl

Creatinine Clearance Formula:

A creatinine clearance test compares the amount of creatinine in your blood to the amount in your urine over a 24-hour period. This shows how fast your kidneys clear creatinine from your body. Your doctor may ask you to do a creatinine clearance test to see how well your kidneys are working.

Creatinine Clearance

50 – 150 ml/mint

Urine Calcium Formula:

Calcium is one of the most common minerals in the body. All cells throughout the body use calcium for various functions. The body uses calcium to build and repair bones and teeth. Calcium also helps nerves, the heart, and muscles function properly, and helps blood to clot.

24 Hours Urine		60 – 300 mg/24 hrs
Spot Urine	Result (mg/dl) x 10	60 – 300 mg/l

Urine Uric Acid Formula:

A uric acid test measures the amount of uric acid in the body. Uric acid is a chemical that’s produced when your body breaks down purines.

24 Hours Urine		250 – 750 mg/24 hrs
Spot Urine	Result (mg/dl) x 10	250 – 750 mg/l

Urine Phosphate Formula:

A urine phosphate test measures how much phosphate is in your pee over a 24-hour period. Your doctor might also call it a phosphorous test.

24 Hours Urine		0.3 – 1.5 g/24 hrs
Spot Urine		0.3 – 1.5 g/l

Urine Urea Formula:

The urine urea nitrogen test determines how much urea is in the urine to assess the amount of protein breakdown. The test can help determine how well the kidneys are functioning and whether your intake of protein is too high or low.

24 Hours Urine		15 – 40 g/24 hrs
Spot Urine		15 – 40 g/l

Osmolality Formula:

Osmolality is a measure of how much one substance has dissolved in another substance. The greater the concentration of the substance dissolved, the higher the osmolality. Very salty water has higher osmolality than water with just a hint of salt.

Urine		50 – 1400 m Osmol/Kg of H2O
Serum		270 – 295 m Osmol/Kg of H2O

Fractional Excretion of Sodium (FENa) Formula:

Fractional excretion of sodium is the amount of salt (sodium) that leaves the body through urine compared to the amount filtered and reabsorbed by the kidney. Fractional excretion of sodium (FENa) is not a test. Instead it is a calculation based on the concentrations of sodium and creatinine in the blood and urine.

Serum		1 – 3 %
Urine		1 – 2 %

Prerenal cause: FENa <1%
Intrinsic Renal cause: FENa 1-4%
Postrenal cause: FENa >4%

Ionized Calcium (Ca²⁺) Formula:

Ionized calcium (Ca²⁺) is calcium in your blood that is not attached to proteins. It is also called free calcium. All cells need calcium in order to work. Calcium helps build strong bones and teeth. It is important for heart function.

Serum

Children = 4.4 – 6.0 mg/dl Adult = 4.4 – 5.3 mg/dl

Transferrin Saturation Formula:

Transferrin saturation (TS), measured as a percentage, is a medical laboratory value. It is the value of serum iron divided by the total iron-binding capacity of the available transferrin, the main protein that binds iron in the blood, this value tells a clinician how much serum iron is bound.

Transferrin Saturation

20 – 55 %

Urine Sodium Formula:

A sodium blood test is a routine test that allows your doctor to see how much sodium is in your blood. It’s also called a serum sodium test.

Spot Urine	Result (m.mol/l)	40 – 220 m.mol/l
24 Hours Urine		40 – 220 m.mol/24 hrs

Urine Potassium Formula:

A potassium blood test measures the amount of potassium in your blood. Potassium is a type of electrolyte. Electrolytes are electrically charged minerals in your body that help control muscle and nerve activity, maintain fluid levels, and perform other important functions.

Spot Urine	Result (m.mol/l)	30 – 80 m.mol/l
24 Hours Urine		30 – 80 m.mol/24 hrs

Urine Chloride Formula:

A chloride blood test is used to diagnose a variety of health conditions. Here’s what the results mean and what happens after taking the test.

Spot Urine	Result (m.mol/l)	140 – 250 m.mol/l
24 Hours Urine		140 – 250 m.mol/24 hrs

Microalbuminuria Formula:

The microalbuminuria test is a urine test that measures the amount of albumin in your urine. Albumin is a protein that your body uses for cell growth and to help repair tissues. It’s normally present in the blood. A certain level of it in your urine may be a sign of kidney damage.

Spot Urine	Result (mg/l)	< 30.0 mg/l
24 Hour Urine		< 30.0 mg/24 hrs

Urine Amylase Formula:

Amylase is an enzyme, or special protein, produced by your pancreas and salivary glands. The pancreas is an organ located behind your stomach.

Spot Urine	Result (U/L)	Upto 48 U/l
45 hrs Urine		Upto 17 U/hrs

Lipid Profile Formula :

Lipid profile or lipid panel is a panel of blood tests that serves as an initial screening tool for abnormalities in lipids, such as cholesterol and triglycerides.

BUN Formula:

A blood urea nitrogen (BUN) test measures the amount of nitrogen in your blood that comes from the waste product urea. Urea is made when protein is broken down in your body. Urea is made in the liver and passed out of your body in the urine. A BUN test is done to see how well your kidneys are working.

INR Formula:

An INR test measures the time for the blood to clot. It is also known as prothrombin time, or PT. It is used to monitor blood-thinning medicines, which are also known as anticoagulants. The INR, or international normalised ratio, can also be used to check if you have a blood clotting problem.

eGFR Formula:

eGFR stands for estimated glomerular filtration rate. It is a measure used to estimate how well the kidneys are functioning in filtering waste products from the blood. The eGFR is calculated using formulas that take into account factors such as age, sex, race, and the blood level of a waste product called creatinine. It is used to assess kidney function and to determine the stage of chronic kidney disease (CKD). A higher eGFR indicates better kidney function, while a lower eGFR suggests decreased kidney function.

eGFR

90 mL/min/1.73m²

Possible References Used

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