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HelpTest ID CRDPP Creatine Disorders Panel, Plasma
Ordering Guidance
For additional diagnostic testing, consider ordering CRDPU / Creatine Disorders Panel, Random, Urine.
Additional Testing Requirements
To diagnose all creatine deficiency syndromes, order CRDPU / Creatine Disorders Panel, Random, Urine in addition to this test.
Necessary Information
Patient's age and sex are required.
Specimen Required
Collection Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Green top (sodium heparin), yellow top (ACD)
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: Centrifuge and aliquot plasma into plastic vial. Send plasma frozen.
Useful For
Evaluating patients with a clinical suspicion of arginine:glycine amidinotransferase deficiency, guanidinoacetate methyltransferase deficiency, and creatine transporter deficiency using plasma specimens
Genetics Test Information
Depletion of cerebral creatine occurs in all 3 types of creatine deficiency syndromes (CDS): arginine:glycine amidinotransferase deficiency, guanidinoacetate methyltransferase deficiency, and creatine transporter deficiency.
Measurement of guanidinoacetate, creatine, and creatinine, along with associated analyte ratios in plasma and urine, aids in distinguishing the types of creatine deficiency syndromes.
Treatment with oral creatine supplementation is effective in some types of CDS.
Creatine supplementation may impact reliability of test results.
Testing Algorithm
For more information see:
-Newborn Screen Follow-up for Guanidinoacetate Methyltransferase Deficiency
-Epilepsy: Unexplained Refractory and/or Familial Testing Algorithm
If the patient has abnormal newborn screening results for guanidinoacetate methyltransferase deficiency, refer to the appropriate ACMG Newborn Screening ACT Sheet.(1)
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Creatine Disorders Panel, PSpecimen Type
PlasmaSpecimen Minimum Volume
0.1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma | Frozen (preferred) | 14 days | |
| Refrigerated | 7 days | ||
| Ambient | 72 hours |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Clinical Information
Disorders of creatine synthesis (guanidinoacetate methyltransferase [GAMT] deficiency, L-arginine:glycine amidinotransferases [AGAT] deficiency, and creatine transporter deficiency [CTD]) are collectively described as creatine deficiency syndromes (CDS). GAMT and AGAT deficiencies are inherited in an autosomal recessive manner, while CTD is X-linked. All 3 disorders result in a depletion of cerebral creatine and typically present with global developmental delays, intellectual disability, and severe speech delay. Affected patients may have abnormal magnetic resonance imaging findings and exhibit cerebral creatine deficiency in brain magnetic resonance spectroscopy. Patients with GAMT and male patients with CTD develop seizures, behavioral problems, and autistic features and may have abnormal movements. Female carriers for CTD can be asymptomatic or exhibit features similar to affected male patients, such as intellectual disability, behavioral problems, and seizures.
Diagnosis of creatine synthesis disorders relies on measurement of guanidinoacetate (GAA), creatine (Cr), and creatinine (Crn) in plasma and urine. The profiles are specific for each clinical entity. In plasma, patients with GAMT deficiency typically exhibit very elevated GAA, low Cr, and normal to low Crn. Patients with AGAT deficiency typically exhibit low to normal GAA, low Cr, and normal to low Crn. Patients with CTD may have normal or abnormal plasma levels of GAA, Cr and Crn, and measurement of these analytes in urine is also useful for diagnosis in male patients (characteristic findings are elevated Cr, normal to low Crn, and an elevated Cr:Crn ratio in urine). The only consistently reliable method for diagnosis of CTD in female patients is molecular analysis of the SLC6A8 gene. The diagnosis of GAMT and AGAT and CTD can be confirmed by molecular analysis of GAMT and GATM and SLC6A8.
Treatment with oral supplementation of creatine monohydrate is available and effective for the AGAT and GAMT deficiencies. Patients with GAMT deficiency may also be treated with supplemental ornithine and dietary arginine restriction.
Early treatment has been reported to prevent disease manifestations in affected but presymptomatic newborn siblings of individuals with GAMT or AGAT deficiencies.
Reference Values
|
Creatine Disorders Panel Reference Values |
||||||||||||
|
|
≤11 Months |
12-23 Months |
24-35 Months |
|||||||||
|
Female |
Male |
Female |
Male |
Female |
Male |
|||||||
|
Creatine |
38.6-96.8 |
39.0-97.0 |
38.2-96.5 |
38.6-96.5 |
37.7-96.0 |
38.2-96.0 |
||||||
|
Creatinine |
27.6-35.9 |
27.6-35.2 |
27.6-36.5 |
27.6-35.5 |
27.6-37.1 |
27.6-36.0 |
||||||
|
Guanidinoacetate |
0.7-2.0 |
0.7-2.1 |
0.7-2.0 |
0.7-2.1 |
0.7-2.0 |
0.7-2.1 |
||||||
|
Creatine/ |
≤3.07 |
≤3.60 |
≤3.02 |
≤3.54 |
≤2.96 |
≤3.48 |
||||||
|
Guanidinoacetate/ |
≤0.040 |
≤0.040 |
≤0.042 |
≤0.040 |
≤0.043 |
≤0.042 |
||||||
|
Guanidinoacetate/ |
≤0.051 |
≤0.081 |
≤0.051 |
≤0.080 |
≤0.051 |
≤0.079 |
||||||
|
|
||||||||||||
|
|
3 Years |
4 Years |
5 Years |
|||||||||
|
Female |
Male |
Female |
Male |
Female |
Male |
|||||||
|
Creatine |
37.1-95.5 |
37.7-95.3 |
36.0-94.4 |
36.8-94.1 |
34.6-93.2 |
35.6-92.7 |
||||||
|
Creatinine |
27.6-37.9 |
27.7-36.9 |
27.6-39.3 |
27.7-38.2 |
27.6-40.9 |
27.8-39.9 |
||||||
|
Guanidinoacetate |
0.7-2.1 |
0.7-2.2 |
0.7-2.1 |
0.7-2.2 |
0.7-2.1 |
0.7-2.2 |
||||||
|
Creatine/ |
≤2.89 |
≤3.40 |
≤2.77 |
≤3.26 |
≤2.64 |
≤3.09 |
||||||
|
Guanidinoacetate/ |
≤0.045 |
≤0.043 |
≤0.049 |
≤0.045 |
≤0.053 |
≤0.049 |
||||||
|
Guanidinoacetate/ |
≤0.050 |
≤0.077 |
≤0.050 |
≤0.075 |
≤0.049 |
≤0.072 |
||||||
|
|
6 Years |
7 Years |
8 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
33.0-91.7 |
34.3-91.0 |
31.2-90.0 |
32.7-89.2 |
29.2-88.1 |
31.0-87.3 |
|
Creatinine |
27.6-42.8 |
28.0-41.9 |
27.7-44.9 |
28.3-44.3 |
27.8-47.0 |
28.8-47.1 |
|
Guanidinoacetate |
0.7-2.1 |
0.7-2.3 |
0.7-2.1 |
0.8-2.3 |
0.8-2.1 |
0.8-2.4 |
|
Creatine/ |
≤2.49 |
≤2.91 |
≤2.33 |
≤2.70 |
≤2.17 |
≤2.49 |
|
Guanidinoacetate/ |
≤0.058 |
≤0.053 |
≤0.063 |
≤0.058 |
≤0.069 |
≤0.064 |
|
Guanidinoacetate/ |
≤0.049 |
≤0.069 |
≤0.048 |
≤0.066 |
≤0.047 |
≤0.063 |
|
|
9 Years |
10 Years |
11 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
27.2-85.9 |
29.3-85.2 |
25.2-83.7 |
27.4-83.1 |
23.4-81.3 |
25.7-80.9 |
|
Creatinine |
28.0-49.3 |
29.5-50.1 |
28.2-51.5 |
30.6-53.6 |
28.4-53.6 |
32.0-57.2 |
|
Guanidinoacetate |
0.8-2.2 |
0.8-2.5 |
0.9-2.2 |
0.9-2.6 |
0.9-2.2 |
1.0-2.6 |
|
Creatine/ |
≤2.02 |
≤2.28 |
≤1.86 |
≤2.07 |
≤1.72 |
≤1.87 |
|
Guanidinoacetate/ |
≤0.075 |
≤0.070 |
≤0.081 |
≤0.078 |
≤0.087 |
≤0.085 |
|
Guanidinoacetate/ |
≤0.047 |
≤0.060 |
≤0.046 |
≤0.057 |
≤0.045 |
≤0.055 |
|
|
12 Years |
13 Years |
14 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
21.7-78.7 |
23.9-78.6 |
20.3-76.2 |
22.3-76.2 |
19.0-73.6 |
20.8-73.8 |
|
Creatinine |
28.7-55.7 |
33.8-61.0 |
29.1-57.7 |
35.9-64.8 |
29.5-59.5 |
38.1-68.5 |
|
Guanidinoacetate |
0.9-2.2 |
1.0-2.7 |
1.0-2.3 |
1.1-2.8 |
1.0-2.3 |
1.1-2.9 |
|
Creatine/ |
≤1.58 |
≤1.68 |
≤1.45 |
≤1.50 |
≤1.33 |
≤1.34 |
|
Guanidinoacetate/ |
≤0.092 |
≤0.093 |
≤0.097 |
≤0.101 |
≤0.101 |
≤0.109 |
|
Guanidinoacetate/ |
≤0.044 |
≤0.053 |
≤0.043 |
≤0.051 |
≤0.042 |
≤0.050 |
|
|
15 Years |
16 Years |
17 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
18.1-71.1 |
19.5-71.2 |
17.4-68.7 |
18.4-68.6 |
16.9-66.5 |
17.4-65.9 |
|
Creatinine |
29.9-61.3 |
40.4-71.9 |
30.4-62.9 |
42.4-75.0 |
30.9-64.4 |
44.2-77.6 |
|
Guanidinoacetate |
1.0-2.3 |
1.2-2.9 |
1.1-2.3 |
1.3-3.0 |
1.1-2.3 |
1.3-3.1 |
|
Creatine/ |
≤1.22 |
≤1.20 |
≤1.12 |
≤1.07 |
≤1.04 |
≤0.97 |
|
Guanidinoacetate/ |
≤0.104 |
≤0.117 |
≤0.107 |
≤0.125 |
≤0.109 |
≤0.132 |
|
Guanidinoacetate/ |
≤0.041 |
≤0.049 |
≤0.040 |
≤0.048 |
≤0.040 |
≤0.048 |
|
|
18 Years |
19 Years |
20 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
16.7-64.4 |
16.6-63.3 |
16.6-62.7 |
15.8-60.7 |
16.5-61.1 |
15.2-58.3 |
|
Creatinine |
31.3-65.8 |
45.6-80.0 |
31.8-67.0 |
46.7-82.0 |
32.2-68.2 |
47.4-83.9 |
|
Guanidinoacetate |
1.1-2.4 |
1.4-3.1 |
1.1-2.4 |
1.4-3.2 |
1.1-2.4 |
1.5-3.2 |
|
Creatine/ |
≤0.98 |
≤0.87 |
≤0.93 |
≤0.80 |
≤0.89 |
≤0.73 |
|
Guanidinoacetate/ |
≤0.111 |
≤0.139 |
≤0.112 |
≤0.145 |
≤0.113 |
≤0.150 |
|
Guanidinoacetate/ |
≤0.039 |
≤0.047 |
≤0.038 |
≤0.047 |
≤0.038 |
≤0.046 |
|
|
21 Years |
22 Years |
23 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
16.6-59.8 |
14.7-56.0 |
16.6-58.8 |
14.2-54.0 |
16.7-57.9 |
13.7-52.2 |
|
Creatinine |
32.5-69.2 |
47.9-85.6 |
 32.8-70.2 |
48.2-87.2 |
 33.1-71.1 |
48.4-88.8 |
|
Guanidinoacetate |
1.1-2.4 |
1.5-3.2 |
1.1-2.5 |
1.5-3.3 |
1.1-2.5 |
1.6-3.3 |
|
Creatine/ |
≤0.87 |
≤0.68 |
≤0.85 |
≤0.64 |
≤0.84 |
≤0.61 |
|
Guanidinoacetate/ |
≤0.114 |
≤0.156 |
≤0.115 |
≤0.161 |
≤0.116 |
≤0.165 |
|
Guanidinoacetate/ |
≤0.037 |
≤0.045 |
≤0.037 |
≤0.045 |
≤0.037 |
≤0.044 |
|
|
24 Years |
25 Years |
26 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
16.7-57.2 |
13.3-50.6 |
16.7-56.5 |
12.9-49.3 |
16.7-56.0 |
12.5-48.1 |
|
Creatinine |
33.3-71.9 |
48.6-90.2 |
33.6-72.8 |
48.7-91.5 |
33.7-73.6 |
48.9-92.7 |
|
Guanidinoacetate |
1.1-2.5 |
1.6-3.3 |
1.1-2.5 |
1.6-3.3 |
1.1-2.6 |
1.6-3.4 |
|
Creatine/ |
≤0.84 |
≤0.58 |
≤0.84 |
≤0.56 |
≤0.84 |
≤0.54 |
|
Guanidinoacetate/ |
≤0.116 |
≤0.170 |
≤0.117 |
≤0.174 |
≤0.118 |
≤0.179 |
|
Guanidinoacetate/ |
≤0.036 |
≤0.043 |
≤0.036 |
≤0.043 |
≤0.036 |
≤0.042 |
|
|
27 Years |
28 Years |
29 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
16.7-55.5 |
12.1-47.1 |
16.6-55.1 |
11.8-46.3 |
16.5-54.7 |
11.5-45.4 |
|
Creatinine |
33.9-74.4 |
49.0-93.7 |
34.1-75.2 |
49.1-94.5 |
34.2-76.0 |
49.2-95.3 |
|
Guanidinoacetate |
1.1-2.6 |
1.6-3.4 |
1.1-2.6 |
1.6-3.4 |
1.1-2.6 |
1.6-3.4 |
|
Creatine/ |
≤0.84 |
≤0.52 |
≤0.84 |
≤0.51 |
≤0.84 |
≤0.49 |
|
Guanidinoacetate/ |
≤0.118 |
≤0.182 |
≤0.119 |
≤0.186 |
≤0.119 |
≤0.188 |
|
Guanidinoacetate/ |
≤0.036 |
≤0.042 |
≤0.036 |
≤0.041 |
≤0.036 |
≤0.041 |
|
|
30 Years |
31 Years |
32 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
16.4-54.2 |
11.3-44.7 |
16.4-53.8 |
11.1-43.9 |
16.3-53.4 |
11.0-43.2 |
|
Creatinine |
34.4-76.8 |
49.3-96.0 |
34.6-77.5 |
49.3-96.7 |
34.7-78.2 |
49.4-97.4 |
|
Guanidinoacetate |
1.2-2.7 |
1.6-3.5 |
1.2-2.7 |
1.6-3.5 |
1.2-2.7 |
1.6-3.5 |
|
Creatine/ |
≤0.84 |
≤0.48 |
≤0.83 |
≤0.47 |
≤0.83 |
≤0.46 |
|
Guanidinoacetate/ |
≤0.120 |
≤0.190 |
≤0.120 |
≤0.192 |
≤0.119 |
≤0.192 |
|
Guanidinoacetate/ |
≤0.036 |
≤0.041 |
≤0.036 |
≤0.042 |
≤0.037 |
≤0.042 |
|
|
33 Years |
34 Years |
35 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
16.3-53.0 |
10.9-42.5 |
16.4-52.7 |
10.8-41.7 |
16.4-52.3 |
10.7-41.0 |
|
Creatinine |
34.9-78.8 |
49.4-98.0 |
35.1-79.4 |
49.5-98.6 |
35.3-79.9 |
49.5-99.2 |
|
Guanidinoacetate |
1.2-2.8 |
1.6-3.5 |
1.2-2.8 |
1.6-3.5 |
1.2-2.8 |
1.6-3.4 |
|
Creatine/ |
≤0.82 |
≤0.45 |
≤0.82 |
≤0.45 |
≤0.82 |
≤0.44 |
|
Guanidinoacetate/ |
≤0.119 |
≤0.192 |
≤0.118 |
≤0.191 |
≤0.118 |
≤0.189 |
|
Guanidinoacetate/ |
≤0.037 |
≤0.042 |
≤0.037 |
≤0.042 |
≤0.037 |
≤0.042 |
|
|
36 Years |
37 Years |
38 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
16.5-52.0 |
10.7-40.2 |
16.7-51.6 |
10.6-39.5 |
16.9-51.3 |
10.6-38.9 |
|
Creatinine |
35.4-80.3 |
49.5-99.8 |
35.6-80.7 |
49.5-100.3 |
35.8-81.0 |
49.6-100.8 |
|
Guanidinoacetate |
1.2-2.8 |
1.6-3.4 |
1.2-2.8 |
1.6-3.4 |
1.2-2.9 |
1.6-3.4 |
|
Creatine/ |
≤0.82 |
≤0.44 |
≤0.82 |
≤0.44 |
≤0.83 |
≤0.44 |
|
Guanidinoacetate/ |
≤0.117 |
≤0.187 |
≤0.115 |
≤0.184 |
≤0.114 |
≤0.182 |
|
Guanidinoacetate/ |
≤0.037 |
≤0.042 |
≤0.037 |
≤0.042 |
≤0.036 |
≤0.042 |
|
|
39 Years |
40 Years |
41 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
17.1-51.1 |
10.6-38.2 |
17.3-50.9 |
10.7-37.7 |
17.5-50.8 |
10.7-37.2 |
|
Creatinine |
35.9-81.4 |
49.6-101.3 |
36.0-81.6 |
49.6-101.7 |
36.1-81.9 |
49.7-102.1 |
|
Guanidinoacetate |
1.2-2.9 |
1.6-3.4 |
1.2-2.9 |
1.6-3.4 |
1.2-2.9 |
1.6-3.4 |
|
Creatine/ |
≤0.83 |
≤0.44 |
≤0.83 |
≤0.44 |
≤0.84 |
≤0.44 |
|
Guanidinoacetate/ |
≤0.113 |
≤0.179 |
≤0.111 |
≤0.176 |
≤0.110 |
≤0.174 |
|
Guanidinoacetate/ |
≤0.036 |
≤0.041 |
≤0.036 |
≤0.041 |
≤0.036 |
≤0.040 |
|
|
42 Years |
43 Years |
44 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
17.7-50.8 |
10.8-36.7 |
17.8-50.8 |
10.9-36.3 |
17.8-50.9 |
11.0-36.0 |
|
Creatinine |
36.2-82.1 |
49.7-102.5 |
36.3-82.4 |
49.8-102.8 |
36.4-82.6 |
49.8-103.1 |
|
Guanidinoacetate |
1.2-3.0 |
1.6-3.3 |
1.2-3.0 |
1.6-3.3 |
1.2-3.0 |
1.6-3.3 |
|
Creatine/ |
≤0.84 |
≤0.44 |
≤0.84 |
≤0.43 |
≤0.84 |
≤0.43 |
|
Guanidinoacetate/ |
≤0.109 |
≤0.172 |
≤0.108 |
≤0.171 |
≤0.107 |
≤0.170 |
|
Guanidinoacetate/ |
≤0.036 |
≤0.039 |
≤0.036 |
≤0.039 |
≤0.036 |
≤0.038 |
|
|
45 Years |
46 Years |
47 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
17.7-51.0 |
11.1-35.6 |
17.6-51.2 |
11.2-35.3 |
17.4-51.4 |
11.3-35.1 |
|
Creatinine |
36.4-82.8 |
49.9-103.4 |
36.5-83.0 |
49.9-103.6 |
36.5-83.2 |
49.9-103.9 |
|
Guanidinoacetate |
1.2-3.0 |
1.7-3.3 |
1.2-3.1 |
1.7-3.3 |
1.2-3.1 |
1.7-3.3 |
|
Creatine/ |
≤0.84 |
≤0.42 |
≤0.83 |
≤0.41 |
≤0.83 |
≤0.40 |
|
Guanidinoacetate/ |
≤0.106 |
≤0.169 |
≤0.106 |
≤0.168 |
≤0.106 |
≤0.167 |
|
Guanidinoacetate/ |
≤0.037 |
≤0.038 |
≤0.037 |
≤0.037 |
≤0.037 |
≤0.037 |
|
|
48 Years |
49 Years |
50 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
17.2-51.7 |
11.5-34.8 |
17.1-51.9 |
11.6-34.6 |
17.0-52.1 |
11.7-34.4 |
|
Creatinine |
36.6-83.4 |
49.9-104.1 |
36.6-83.5 |
49.9-104.2 |
36.7-83.7 |
49.9-104.4 |
|
Guanidinoacetate |
1.2-3.1 |
1.7-3.3 |
1.2-3.1 |
1.7-3.3 |
1.2-3.1 |
1.7-3.3 |
|
Creatine/ |
≤0.82 |
≤0.39 |
≤0.82 |
≤0.38 |
≤0.82 |
≤0.38 |
|
Guanidinoacetate/ |
≤0.106 |
≤0.166 |
≤0.106 |
≤0.164 |
≤0.105 |
≤0.163 |
|
Guanidinoacetate/ |
≤0.038 |
≤0.036 |
≤0.038 |
≤0.036 |
≤0.039 |
≤0.036 |
|
|
51 Years |
52 Years |
53 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
17.0-52.2 |
11.9-34.3 |
17.1-52.3 |
12.0-34.3 |
17.3-52.4 |
12.2-34.3 |
|
Creatinine |
36.8-83.9 |
49.8-104.6 |
36.8-84.0 |
49.8-104.8 |
36.9-84.2 |
49.8-104.9 |
|
Guanidinoacetate |
1.2-3.1 |
1.7-3.3 |
1.2-3.1 |
1.7-3.2 |
1.2-3.1 |
1.6-3.2 |
|
Creatine/ |
≤0.82 |
≤0.37 |
≤0.82 |
≤0.37 |
≤0.82 |
≤0.38 |
|
Guanidinoacetate/ |
≤0.105 |
≤0.161 |
≤0.104 |
≤0.159 |
≤0.103 |
≤0.157 |
|
Guanidinoacetate/ |
≤0.039 |
≤0.036 |
≤0.039 |
≤0.036 |
≤0.039 |
≤0.036 |
|
|
54 Years |
55 Years |
56 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
17.6-52.5 |
12.4-34.3 |
18.1-52.6 |
12.5-34.4 |
18.6-52.7 |
12.6-34.4 |
|
Creatinine |
37.0-84.4 |
49.8-105.0 |
37.1-84.5 |
49.8-105.2 |
37.2-84.7 |
49.8-105.3 |
|
Guanidinoacetate |
1.2-3.1 |
1.6-3.2 |
1.2-3.1 |
1.6-3.2 |
1.2-3.1 |
1.6-3.2 |
|
Creatine/ |
≤0.82 |
≤0.38 |
≤0.83 |
≤0.39 |
≤0.84 |
≤0.40 |
|
Guanidinoacetate/ |
≤0.102 |
≤0.155 |
≤0.100 |
≤0.154 |
≤0.099 |
≤0.152 |
|
Guanidinoacetate/ |
≤0.039 |
≤0.036 |
≤0.039 |
≤0.036 |
≤0.039 |
≤0.036 |
|
|
57 Years |
58 Years |
59 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
19.2-52.9 |
12.7-34.4 |
19.9-53.1 |
12.8-34.3 |
20.5-53.3 |
12.8-34.2 |
|
Creatinine |
37.3-84.9 |
49.8-105.4 |
37.4-85.1 |
49.8-105.5 |
37.6-85.2 |
49.8-105.6 |
|
Guanidinoacetate |
1.2-3.0 |
1.6-3.2 |
1.3-3.0 |
1.6-3.2 |
1.3-3.0 |
1.6-3.2 |
|
Creatine/ |
≤0.84 |
≤0.40 |
≤0.85 |
≤0.41 |
≤0.86 |
≤0.42 |
|
Guanidinoacetate/ |
≤0.098 |
≤0.151 |
≤0.096 |
≤0.151 |
≤0.095 |
≤0.150 |
|
Guanidinoacetate/ |
≤0.039 |
≤0.036 |
≤0.038 |
≤0.036 |
≤0.038 |
≤0.036 |
|
|
60 Years |
61 Years |
62 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
21.0-53.6 |
12.8-34.1 |
21.5-53.9 |
12.7-34.0 |
21.9-54.2 |
12.6-33.9 |
|
Creatinine |
37.8-85.4 |
49.9-105.7 |
38.0-85.5 |
49.9-105.9 |
38.3-85.7 |
49.9-106.0 |
|
Guanidinoacetate |
1.3-2.9 |
1.6-3.2 |
1.3-2.9 |
1.6-3.1 |
1.3-2.9 |
1.6-3.1 |
|
Creatine/ |
≤0.87 |
≤0.43 |
≤0.87 |
≤0.44 |
≤0.88 |
≤0.44 |
|
Guanidinoacetate/ |
≤0.094 |
≤0.150 |
≤0.093 |
≤0.150 |
≤0.093 |
≤0.150 |
|
Guanidinoacetate/ |
≤0.037 |
≤0.036 |
≤0.036 |
≤0.035 |
≤0.036 |
≤0.035 |
|
|
63 Years |
64 Years |
65 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
22.2-54.6 |
12.4-33.7 |
22.3-55.0 |
12.3-33.6 |
22.5-55.5 |
12.2-33.4 |
|
Creatinine |
38.7-85.8 |
50.0-106.1 |
39.1-85.9 |
50.0-106.3 |
39.6-86.1 |
50.1-106.4 |
|
Guanidinoacetate |
1.3-2.8 |
1.6-3.1 |
1.3-2.8 |
1.6-3.1 |
1.3-2.8 |
1.6-3.1 |
|
Creatine/ |
≤0.88 |
≤0.45 |
≤0.89 |
≤0.46 |
≤0.89 |
≤0.46 |
|
Guanidinoacetate/ |
≤0.092 |
≤0.150 |
≤0.092 |
≤0.149 |
≤0.091 |
≤0.149 |
|
Guanidinoacetate/ |
≤0.035 |
≤0.035 |
≤0.034 |
≤0.034 |
≤0.034 |
≤0.034 |
|
|
66 Years |
67 Years |
68 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
22.6-55.9 |
12.3-33.1 |
22.7-56.3 |
12.3-32.8 |
22.9-56.7 |
12.5-32.4 |
|
Creatinine |
40.2-86.2 |
50.2-106.6 |
40.7-86.3 |
50.3-106.7 |
41.3-86.5 |
50.4-106.9 |
|
Guanidinoacetate |
1.3-2.7 |
1.6-3.1 |
1.3-2.7 |
1.6-3.0 |
1.4-2.7 |
1.6-3.0 |
|
Creatine/ |
≤0.90 |
≤0.47 |
≤0.90 |
≤0.48 |
≤0.90 |
≤0.48 |
|
Guanidinoacetate/ |
≤0.091 |
≤0.149 |
≤0.090 |
≤0.148 |
≤0.090 |
≤0.148 |
|
Guanidinoacetate/ |
≤0.034 |
≤0.034 |
≤0.033 |
≤0.034 |
≤0.033 |
≤0.034 |
|
|
69 Years |
70 Years |
≥ 71 Years |
|||
|
Female |
Male |
Female |
Male |
Female |
Male |
|
|
Creatine |
23.2-57.0 |
12.8-32.0 |
23.6-57.2 |
13.1-31.4 |
24.1-57.3 |
13.6-30.8 |
|
Creatinine |
41.9-86.6 |
50.5-107.1 |
42.4-86.8 |
50.7-107.4 |
42.8-86.9 |
50.8-107.6 |
|
Guanidinoacetate |
1.4-2.6 |
1.6-3.0 |
1.4-2.6 |
1.6-3.0 |
1.4-2.5 |
1.5-3.0 |
|
Creatine/ |
≤0.90 |
≤0.48 |
≤0.90 |
≤0.48 |
≤0.90 |
≤0.48 |
|
Guanidinoacetate/ |
≤0.090 |
≤0.148 |
≤0.090 |
≤0.148 |
≤0.090 |
≤0.148 |
|
Guanidinoacetate/ |
≤0.033 |
≤0.034 |
≤0.033 |
≤0.034 |
≤0.033 |
≤0.034 |
Interpretation
Reports include concentrations of guanidinoacetate, creatine, and creatinine, and the calculated analyte ratios. When no significant abnormalities are detected, a simple descriptive interpretation is provided. When abnormal results are detected, a detailed interpretation is given. This interpretation includes an overview of the results and their significance, a correlation to available clinical information, elements of differential diagnosis, and recommendations for additional biochemical testing.
Cautions
Creatine supplementation will cause falsely elevated creatine results and falsely decreased guanidinoacetate results.
Guanidinoacetate can be elevated in patients with urea cycle defects.
Clinical Reference
1. ACMG Newborn Screening ACT Sheets. Accessed October 30, 2023. Available at www.acmg.net/ACMG/Medical-Genetics-Practice-Resources/ACT_Sheets_and_Algorithms/ACMG/Medical-Genetics-Practice-Resources/ACT_Sheets_and_Algorithms.aspx?hkey=9d6bce5a-182e-42a6-84a5-b2d88240c508
2. Sanders K, Peck D, Bentz Pino G, et al. SLC6A8 creatine transporter deficiency can be detected by plasma creatine and creatinine concentrations. Mol Genet Metab. 2024;142(1):108455. doi:10.1016/j.ymgme.2024.108455
3. Clark JF, Cecil KM. Diagnostic methods and recommendations for the cerebral creatine deficiency syndromes. Pediatr Res. 2015;77(3):398-405
4. Mercimek-Mahmutoglu S, Salomons GS. Creatine deficiency syndromes. In: Adam MP, Mirzaa GM, Pagon RA, et al. eds. GeneReviews [Internet]. University of Washington, Seattle; 2009. Updated February 10, 2022. Accessed March 30, 2023. Available at www.ncbi.nlm.nih.gov/books/NBK3794/
5.. Stockler S, Schultz PW, Salomons GS. Cerebral creatine deficiency syndromes: clinical aspects, treatment, and pathophysiology. Subcell Biochem. 2007;46:149-166
6.. Longo N, Ardon O, Vanzo R, et al. Disorders of creatine transport and metabolism. Am J Med Genet. 2011;157:72-78. doi:10.1002/ajmg.c.30292
Method Description
A plasma sample is combined with stable isotope-labeled internal standards and acetonitrile. After centrifugation, an aliquot of this diluted sample is analyzed by injection onto liquid chromatography columns that separate the analytes from the bulk of the stable isotope dilution in the positive electrospray selected reaction monitoring mode using the Applied Biosystems API 3200 liquid chromatography tandem mass spectrometry system with Analyst software.(Bodamer OA, Bloesch SM, Gregg AR, Stockler-Ipsiroglu S, O'Brien WEO. Analysis of guanidinoacetate and creatine by isotope dilution electroscopy tandem mass spectrometry. Clin Chim Acta. 2001;308:173-178; Cognat S, Cheillan D, Piraud M, Roos B, Jakobs C, Vianey-Saban C. Determination of guanidinoacetate and creatine in urine and plasma by liquid chromatography-tandem mass spectrometry. Clin Chem. 2004;50(8):1459-1461; Sharer JD, Bodamer O, Longo N, Tortorelli S, Wamelink M, Young S. Laboratory diagnosis of creatine deficiency syndromes: a technical standard and guideline of the American College of Medical Genetics and Genomics. Genet Med. 2017;19[2]:256-263)
Day(s) Performed
Tuesday
Report Available
3 to 9 daysTest Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
82540
82565
82542
NY State Approved
YesForms
1. Biochemical Genetics Patient Information (T602)
2. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.