Acute Kidney Injury

Diagnosis of AKI and Interprofessional collaboration

Jennifer Kong

Learning Objectives

By the end of this chapter, you will be able to:

  • Explain the role of blood and urine tests in the diagnosis of AKI
  • Briefly describe how ultrasound works and the role of the sonographer when diagnosing AKI

Medical Lab Technologist

As mentioned earlier, kidney function is mainly determined on blood tests, urine composition, and urine volume.  A medical lab technologist is responsible for collecting and analyzing both blood and urine samples.  Blood tests will be analyzed for creatinine and nitrogen waste (e.g. urea) levels in the blood; urine tests can analyze for composition that suggests the kidney’s ability to reabsorb useful nutrients, electrolytes, and overall fluid volume and density.  In addition, blood tests can be analyzed to help identify the cause (i.e. pre-renal, intrarenal, or post-renal)

Sonographer

A sonographer uses ultrasound to help investigate the cause of AKI.  Ultrasound can give real time information on kidney structure and the path of urine excretion.  Ultrasound can also give information of blood flow to/from the kidney (Doppler for blood flow) which will help determine the cause of AKI being pre-renal vs intrarenal/post-renal causes.

Sonography and acute kidney injury. Created by Ken Marken and Jennifer Kong under a CC-BY-NC license.

Section Summary

Many health professionals work together to diagnose AKI and determine the severity.  Medical lab technologists can test the presence of wastes in the blood, indicative of an impaired elimination from the renal system.  Similarly, they can test for the presence of useful nutrients in the urine, indicative of impaired reabsorption at the nephron level.  Sonographers can give real-time imaging of blood flow to the kidney and of the kidney itself.  This is helpful for prerenal causes as sonographers can use the ‘doppler’ to measure blood flow to the kidney and for post-rental causes as an obstruction can be visualized.

Review questions

1. A medical lab technologist can help determine kidney function by measuring substances? Select all that apply.

  • Blood plasma or serum
  • Feces
  • Urine
  • Hair

 

2. Sonography can detect the presence of a blood clot to the kidney.

  • True
  • False

 

3. Why are medical lab technologists are measuring nitrogen waste levels in blood and not urine? 

 

 

Answer Key

  1. Blood plasma or serum, Urine
  2. True
  3. Kidney failure means you can’t eliminate the nitrogenous wastes from your blood into your urine.  You would expect to see nitrogen waste in urine at all times – but there should be much nitrogen in your blood if your kidneys work.

 

License

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Pathology Copyright © 2022 by Jennifer Kong is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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