Author: The Mislabeled Specimen

Determine the 24 hour creatinine clearance in ml/min using the measured serum and urine creatinine and total volume. Formula: Creatinine Clearance = Urine Creatinine x 24 hour Urine Total Volume / Serum Creatinine / 1440 Principle: Creatinine clearance is the theoretical volume of blood which is wholly cleared of creatinine following one passage through the kidney.… Continue reading 24 Hr Creatinine Clearance

Calculate the Estimated Glomerular Filtration Rate (eGFR) using the patient's serum creatinine level, age, race and sex. Formula: The IDMS-traceable MDRD study equationGFR = 175 × (SCr)-1.154 × (age)-0.203 × (0.742 if female) × (1.212 if Black)where SCr = serum creatinine in mg/dL The CKD-EPI formulaBlack femaleIf SCr < 0.7GFR = 166 × (SCr/0.7)-0.329 × 0.993ageIf SCr > 0.7GFR = 166 ×… Continue reading Estimated GFR

Calculate the volume of a 75 gram or 100 gram glucose load based on the pediatric patient's weight in kilograms. Formula: Volume (oz) = Weight in kilogram x 0.233 oz of 75G Glucose Solution per kilogram body weight Volume (oz) = Weight in kilogram x 0.175 oz of 100G Glucose Solution per kilogram body weight… Continue reading Pediatric OGTT

Percent difference is calculated as the difference between two values, divided by the average of the two values, expressed in terms of percentage. Formula: %Difference = (Value A - Value B) / (Value A + Value B) / 2 x 100 Using Absolute Values While calculating the percent difference, always use absolute values, i.e. ignore… Continue reading Percent Difference

Calculator used to determine the amount of diluent need to get the desired concentration of a known solution. Formula: Initial Concentration (C1) x Initial Volume (V1) = Final Concentration (C2) x Final Volume (V2)Volume of Diluent Needed = Final Volume (V2) - Initial Volume (V1) Principle: Dilution is the process of decreasing the concentration of a solute in… Continue reading Solution Dilution

Manually calculate the sample's INR with the sample's prothrombin Time, average prothrombin time of normal patients, and the reagent's ISI. Formula: INR = (Sample Prothrombin Time / Normal Patients' Prothrombin Time) ISI Principle: The International Normalized Ratio (INR)/International Sensitivity Index (ISI) system was developed as a way to standardize the prothrombin time during the monitoring… Continue reading INR Manual Calculation

Calculate Absolute Neutrophil Count from the Relative Neutrophil Count and total WBC count. Formula: Absolute Neutrophil Count (ANC) = WBC Count (/uL) x Relative Neutrophil Count (%Neutrophil) Indication: An absolute neutrophil count may be used to check for infection, inflammation, leukemia, and other conditions. The lower a person's absolute neutrophil count is, the higher the risk… Continue reading Absolute Neutrophil Count

Calculate the iron saturation (%) from the ratio between serum iron and total iron binding capacity (TIBC). Formula: The percentage saturation of transferrin with iron is calculated by dividing the serum iron concentration by the total iron binding capacity (TIBC) and multiplying by 100. Interpretation of Saturation Values: Transferrin saturation, measured as a percentage, helps… Continue reading Iron Saturation

Calculates gap from the difference between the cations (sodium & potassium) and anions (chloride and bicarbonate) to assess acid base balance. Formula: Anion Gap (mEq/L) = Sodium (mEq/L) + Potassium (mEq/L) - Chloride (mEq/L) - Bicarbonate (mEq/L) Principle: The anion gap (AG) is a measure of acid-base balance. Your body maintains balance by holding onto… Continue reading Anion Gap

Calculates the Mean Corpuscular Volume (MCV), Mean Corpuscular Hemoglobin (MCH), and the Mean Corpuscular Hemoglobin Concentration (MCHC) using Hemoglobin, Hematocrit and RBC Levels. Formula: Mean Corpuscular Volume (MCV) = Hematocrit (%) x 10 / RBC Count in millions/uLMean Corpuscular Hemoglobin (MCH) = Hemoglobin (g/dL) x 10 / RBC Count in millions /uLMean Corpuscular Hemoglobin Concentration… Continue reading RBC Indices