Lab Values
| Common Lab Values Chart | |
| BUN | 8-22mg/dL |
| Creatinine | 0.6-1.2mg/dL |
| PT (Prothrombin Time) | 11-16 seconds |
| PTT (Partial thromboplastin time) | 25-38 seconds |
| INR (International Normalized Ratio) | 0.8-1.2 |
| Platelet Count | 150,000-350,000µL |
| Albumin | 3.2-4.5 g/dL |
| Bilirubin | 0.1-1.0 mg/dL |
| d-dimer | Normal range varies |
- The lab values listed in the figure above are important for a CT Technologist to know and understand. The ability for a patient to receive iodinated contrast will depend directly on these values.
- A patient’s renal function is indicated by the levels of blood urea nitrogen (BUN) and creatinine present. These levels can be examined either as a ratio or individually.
- Normal BUN values in adults range from 8 to 22 mg/dL
- By itself, BUN is not a sufficient indicator of renal insufficiency.
- Normal creatinine levels range from 0.6-1.2 mg/dL
- Normal BUN values in adults range from 8 to 22 mg/dL
- A more accurate measure of renal function is GFR (Glomerular filtration rate). eGFR (estimated GFR) is an estimation of the rate in which the bloodstream filters creatinine.
- To calculate eGFR the following is needed
- Patient’s measured serum creatinine level.
- Patient’s age, sex, and race.
- Normal kidney function as determined by eGFR is a measurement greater than 90, but is often displayed as >60.
- Abnormal or decreasing kidney function is shown by an eGFR measurement lower than the normal range, but is often displayed as a number <60.
- Blood coagulation is measured by PT or Prothrombin time.
- To measure PT, a protein called tissue factor is added to the blood sample.
- 11 to 16 seconds is normal range for PT.
- INR (international normalized ratio) is calculated to help standardize PT results. This is done because there can be differences in the batches of tissue factor as they are manufactured.
- The PT result is compared with a control sample using the INR.
- 0.8-1.2 is normal range for INR.
- Abnormalities in blood clotting are detected by PTT (Partial thromboplastin time).
- 25 to 38 seconds is normal range for clotting time.
- Clotting ability is determined by platelet count.
- 150,000-350,000µL of blood is normal platelet count.
- Â Deep vein thrombosis and pulmonary embolisms may be detected through d-Dimer testing. An elevated d-Dimer in the bloodstream can indicate fragmented protein in the blood, from the breaking down of blood clots. A CT Pulmonary Angiography may be performed of the pulmonary arteries if the d-Dimer value is elevated.
- To screen liver damage, an LFT (liver function test) is performed.
- To perform an LFT, a panel of blood tests that measure different enzymes and proteins in the blood as it is circulating is run.