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Test 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, P

Specimen Type

Plasma

Specimen 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

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
(creatine, creatinine, and guanidinoacetate results reported as nmol/mL)

 

≤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/
creatinine

≤3.07

≤3.60

≤3.02

≤3.54

≤2.96

≤3.48

Guanidinoacetate/
creatine

≤0.040

≤0.040

≤0.042

≤0.040

≤0.043

≤0.042

Guanidinoacetate/
creatinine

≤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/
creatinine

≤2.89

≤3.40

≤2.77

≤3.26

≤2.64

≤3.09

Guanidinoacetate/
creatine

≤0.045

≤0.043

≤0.049

≤0.045

≤0.053

≤0.049

Guanidinoacetate/
creatinine

≤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/
creatinine

≤2.49

≤2.91

≤2.33

≤2.70

≤2.17

≤2.49

Guanidinoacetate/
creatine

≤0.058

≤0.053

≤0.063

≤0.058

≤0.069

≤0.064

Guanidinoacetate/
creatinine

≤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/
creatinine

≤2.02

≤2.28

≤1.86

≤2.07

≤1.72

≤1.87

Guanidinoacetate/
creatine

≤0.075

≤0.070

≤0.081

≤0.078

≤0.087

≤0.085

Guanidinoacetate/
creatinine

≤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/
creatinine

≤1.58

≤1.68

≤1.45

≤1.50

≤1.33

≤1.34

Guanidinoacetate/
creatine

≤0.092

≤0.093

≤0.097

≤0.101

≤0.101

≤0.109

Guanidinoacetate/
creatinine

≤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/
creatinine

≤1.22

≤1.20

≤1.12

≤1.07

≤1.04

≤0.97

Guanidinoacetate/
creatine

≤0.104

≤0.117

≤0.107

≤0.125

≤0.109

≤0.132

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.98

≤0.87

≤0.93

≤0.80

≤0.89

≤0.73

Guanidinoacetate/
creatine

≤0.111

≤0.139

≤0.112

≤0.145

≤0.113

≤0.150

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.87

≤0.68

≤0.85

≤0.64

≤0.84

≤0.61

Guanidinoacetate/
creatine

≤0.114

≤0.156

≤0.115

≤0.161

≤0.116

≤0.165

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.84

≤0.58

≤0.84

≤0.56

≤0.84

≤0.54

Guanidinoacetate/
creatine

≤0.116

≤0.170

≤0.117

≤0.174

≤0.118

≤0.179

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.84

≤0.52

≤0.84

≤0.51

≤0.84

≤0.49

Guanidinoacetate/
creatine

≤0.118

≤0.182

≤0.119

≤0.186

≤0.119

≤0.188

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.84

≤0.48

≤0.83

≤0.47

≤0.83

≤0.46

Guanidinoacetate/
creatine

≤0.120

≤0.190

≤0.120

≤0.192

≤0.119

≤0.192

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.82

≤0.45

≤0.82

≤0.45

≤0.82

≤0.44

Guanidinoacetate/
creatine

≤0.119

≤0.192

≤0.118

≤0.191

≤0.118

≤0.189

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.82

≤0.44

≤0.82

≤0.44

≤0.83

≤0.44

Guanidinoacetate/
creatine

≤0.117

≤0.187

≤0.115

≤0.184

≤0.114

≤0.182

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.83

≤0.44

≤0.83

≤0.44

≤0.84

≤0.44

Guanidinoacetate/
creatine

≤0.113

≤0.179

≤0.111

≤0.176

≤0.110

≤0.174

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.84

≤0.44

≤0.84

≤0.43

≤0.84

≤0.43

Guanidinoacetate/
creatine

≤0.109

≤0.172

≤0.108

≤0.171

≤0.107

≤0.170

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.84

≤0.42

≤0.83

≤0.41

≤0.83

≤0.40

Guanidinoacetate/
creatine

≤0.106

≤0.169

≤0.106

≤0.168

≤0.106

≤0.167

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.82

≤0.39

≤0.82

≤0.38

≤0.82

≤0.38

Guanidinoacetate/
creatine

≤0.106

≤0.166

≤0.106

≤0.164

≤0.105

≤0.163

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.82

≤0.37

≤0.82

≤0.37

≤0.82

≤0.38

Guanidinoacetate/
creatine

≤0.105

≤0.161

≤0.104

≤0.159

≤0.103

≤0.157

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.82

≤0.38

≤0.83

≤0.39

≤0.84

≤0.40

Guanidinoacetate/
creatine

≤0.102

≤0.155

≤0.100

≤0.154

≤0.099

≤0.152

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.84

≤0.40

≤0.85

≤0.41

≤0.86

≤0.42

Guanidinoacetate/
creatine

≤0.098

≤0.151

≤0.096

≤0.151

≤0.095

≤0.150

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.87

≤0.43

≤0.87

≤0.44

≤0.88

≤0.44

Guanidinoacetate/
creatine

≤0.094

≤0.150

≤0.093

≤0.150

≤0.093

≤0.150

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.88

≤0.45

≤0.89

≤0.46

≤0.89

≤0.46

Guanidinoacetate/
creatine

≤0.092

≤0.150

≤0.092

≤0.149

≤0.091

≤0.149

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.90

≤0.47

≤0.90

≤0.48

≤0.90

≤0.48

Guanidinoacetate/
creatine

≤0.091

≤0.149

≤0.090

≤0.148

≤0.090

≤0.148

Guanidinoacetate/
creatinine

≤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/
creatinine

≤0.90

≤0.48

≤0.90

≤0.48

≤0.90

≤0.48

Guanidinoacetate/
creatine

≤0.090

≤0.148

≤0.090

≤0.148

≤0.090

≤0.148

Guanidinoacetate/
creatinine

≤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.

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

Day(s) Performed

Tuesday

Report Available

3 to 9 days

Test 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

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CRDPP Creatine Disorders Panel, P 104537-6

 

Result ID Test Result Name Result LOINC Value
608071 Interpretation 104538-4
608072 Creatine 15045-8
608073 Creatinine 14682-9
608074 Guanidinoacetate 33244-5
608075 Creatine/Creatinine 104539-2
610624 Guanidinoacetate/Creatine 105124-2
610856 Guanidinoacetate/Creatinine 104540-0
608076 Reviewed By 18771-6

Forms

1. Biochemical Genetics Patient Information (T602)

2. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.

Mayo Clinic Laboratories | Genetics and Genomics Additional Information:

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