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Official Description

Phenylketones, qualitative

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

Phenylketones are organic compounds that can be detected in urine, primarily as a consequence of a genetic disorder known as phenylketonuria (PKU). This condition arises from a deficiency in the enzyme phenylalanine hydroxylase (PAH), which is crucial for the metabolism of the amino acid phenylalanine. When PAH is nonfunctional, phenylalanine accumulates in the bloodstream, leading to its conversion into phenylketones. These phenylketones are then filtered by the kidneys and excreted in the urine. The qualitative testing for phenylketones in urine is an important diagnostic tool for identifying PKU, allowing for timely intervention and management of the disorder to prevent potential neurological damage and other complications associated with elevated phenylalanine levels.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The qualitative testing for phenylketones in urine is indicated for the following conditions:

  • Phenylketonuria (PKU) This inherited metabolic disorder requires monitoring for phenylketones to manage phenylalanine levels effectively.
  • Newborn Screening Infants are routinely screened for PKU to ensure early diagnosis and treatment, preventing severe developmental issues.
  • Monitoring Treatment Efficacy Patients diagnosed with PKU may undergo periodic testing to assess the effectiveness of dietary restrictions and other therapeutic interventions.

2. Procedure

The procedure for testing phenylketones in urine involves several key steps that ensure accurate results. First, a urine sample is collected from the patient, which should be handled according to standard laboratory protocols to prevent contamination. Next, the sample is subjected to qualitative analysis, which may include chemical tests or colorimetric assays designed to detect the presence of phenylketones. The laboratory technician will observe any color changes or reactions that indicate the presence of these compounds. Finally, the results are documented and interpreted by a qualified healthcare professional, who will communicate the findings to the patient or referring physician for further action if necessary.

  • Step 1: Sample Collection A clean-catch urine sample is obtained from the patient, ensuring that the sample is free from contaminants that could affect the test results.
  • Step 2: Qualitative Analysis The urine sample undergoes qualitative testing, which may involve specific reagents that react with phenylketones, producing observable changes that indicate their presence.
  • Step 3: Result Interpretation The results of the test are analyzed by a healthcare professional, who will determine the significance of the findings in the context of the patient's health status.

3. Post-Procedure

After the qualitative testing for phenylketones is completed, the patient may not require any specific post-procedure care, as the test is non-invasive. However, it is essential for the healthcare provider to discuss the results with the patient, especially if phenylketones are detected. If the test indicates the presence of phenylketones, further evaluation and management strategies will be necessary, which may include dietary modifications or additional testing to monitor phenylalanine levels. Patients diagnosed with PKU will need ongoing support and education regarding their condition to ensure proper management and prevent complications.

Short Descr ASSAY OF PHENYLKETONES
Medium Descr ASSAY OF PHENYLKETONES QUALITATIVE
Long Descr Phenylketones, qualitative
Status Code Statutory Exclusion (from MPFS, may be paid under other methodologies)
Global Days XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC) 9 - Not Applicable
Multiple Procedures (51) 9 - Concept does not apply.
Bilateral Surgery (50) 9 - Concept does not apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 9 - Concept does not apply.
Co-Surgeons (62) 9 - Concept does not apply.
Team Surgery (66) 9 - Concept does not apply.
Diagnostic Imaging Family 99 - Concept Does Not Apply
CLIA Waived (QW) No
APC Status Indicator Conditionally packaged laboratory tests
Type of Service (TOS) 5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS) T1H - Lab tests - other (non-Medicare fee schedule)
MUE 1
CCS Clinical Classification 233 - Laboratory - Chemistry and Hematology
Date
Action
Notes
2013-01-01 Changed Medium Descriptor changed.
Pre-1990 Added Code added.
Code
Description
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