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Homogentisic Acid, Urine (Referred out) - Saskatoon

Discipline

Metabolic Diseases Laboratory Tests

Overview

Alias

  • Alkaptonuria

Specimen Information

Specimen types accepted

  • Random Urine

Specimen collection container

Required volume

  • Optimal volume: 10 mL urine
  • Minimum volume: 3 mL urine

(Submitting the minimum volume makes it impossible to repeat the test or perform confirmatory/reflex testing. In some situations, a minimum volume may require a second collection.)
 

Transport and stability

  • Send to SPH on an ice pack. 
  • Freeze immediately upon receipt in the lab. 
  • Ship frozen to referral laboratory

Rejection criteria

Testing Information

Relevant clinical history

  • Family history
  • Must include diagnosis and/or patient symptoms on the requisition.
     

Clinical interpretation

  • Result interpretation should be correlated with clinical and other laboratory findings.

Performance

Days/times performed

  • Availability - Shipped daily Monday to Sunday
  • Testing site - Referred out by St. Paul’s Hospital Laboratory to Roy Romanow Provincial laboratory

Maximum laboratory time

  • 7 day turnaround time by referral laboratory
     

Other information

  • Relevant Recent medication History - Aspirin may produce an increase in homogentisic acid

Additional comments  

  • This test is useful for the diagnosis of alkaptonuria caused by the enzymatic defects in homogentisate-1, 2-dioxygenase. The main finding in children with alkaptonuria is the presence of dark urine due to the formation of melanin-like polymers in a process termed ochronosis (dark tissue pigmentation). Later in life the darkening of cartilage can occur along with bone and connective tissue diseases resulting in painful arthritic complications. Patients might present cardiac symptoms and develop kidney stones related to pigment crystallization. 
  • Homogentisic Acid is processed as part of the Organic Acids Qualitative – Urine  Screen

Last Updated: October 18, 2024