Delayed puberty laboratory findings: Difference between revisions
Jump to navigation
Jump to search
No edit summary |
No edit summary |
||
| Line 22: | Line 22: | ||
There are no diagnostic laboratory findings associated with [disease name]. | There are no diagnostic laboratory findings associated with [disease name]. | ||
==Laboratory Findings== | ==Laboratory Findings== | ||
*Some patients with | === Biochemistry laboratory tests === | ||
*In order to evaluating any other underlying diseases, many biochemistry lab tests could be considered. These lab tests are including complete blood count, erythrocyte sedimentation rate, creatinine, electrolytes, bicarbonate, alkaline phosphatase, albumin, thyrotropin, and free thyroxine. | |||
*In case of specific familial disorders, some especial lab tests may be needed, indeed. These lab tests are including anti-gliadin antibody and anti-tissue transglutaminase antibody (i.e., celiac disease diagnosis) or anti-neutrophil cythoplasmic antibodies (i.e., inflammatory bowel disease diagnosis). | |||
==== Complete blood count ==== | |||
Some patients with delayed puberty may have reduced concentration of hemoglobin, which is usually suggestive of anemia as underlying cause. | |||
Some patients with delayed puberty may have elevated number of lymphocytes, which is usually suggestive of viral infections (mumps, coxsackie) as underlying cause. | |||
Decreasing number of lymphocytes (especially CD4s) may reveal AIDS, as underlying cause of delayed puberty. | |||
==== Erythrocyte sedimentation rate ==== | |||
An elevated erythrocyte sedimentation rate (ESR) is diagnostic of most of the underlying diseases that may cause delayed puberty. | |||
==== Creatinine ==== | |||
Some patients with delayed puberty may have elevated concentration of creatinine, which is usually suggestive of renal disease as underlying cause. | |||
==== Electrolytes ==== | |||
Some patients with delayed puberty may have elevated serum sodium, potassium, or any other electrolytes, which is usually suggestive of renal disease as underlying cause. | |||
Increasing calcium and magnesium may reflect the effect of radiation or chemotherapy as the cause of delayed puberty. | |||
==== Bicarbonate ==== | |||
Reduced Bicarbonate concentration in serum may reveal the metabolic acidosis due to various causes, mostly chronic kidney injury, as underlying cause of delayed puberty. | |||
==== Alkaline phosphatase ==== | |||
An elevated/reduced concentration of serum alkaline phosphatase is diagnostic of any liver or bone diseases, as underlying cause of delayed puberty. | |||
Histiocytosis, galactosemia induced hepatomgaly, and Gaucher's diseases are some of examples. | |||
==== Albumin ==== | |||
Some patients with delayed puberty may have reduced concentration of serum albumin, which is usually suggestive of liver or renal disease as underlying cause. | |||
==== Thyrotropin ==== | |||
An elevated concentration of serum thyroid stimulating hormone (TSH) is diagnostic of hypothyroidism, as underlying cause of delayed puberty. | |||
==== Free thyroxine ==== | |||
An reduced concentration of serum free thyroxine (T4) is diagnostic of hypothyroidism, as underlying cause of delayed puberty. | |||
==== Anti-gliadin antibody ==== | |||
Some patients with delayed puberty may have positive anti gliadin antibody, which is usually suggestive of Celiac disease as underlying cause. | |||
==== Anti-tissue transglutaminase antibody ==== | |||
Some patients with delayed puberty may have positive anti tissue transglutaminase antibody, which is usually suggestive of Celiac disease as underlying cause. | |||
==== Anti-neutrophil cythoplasmic antibodies ==== | |||
Some patients with delayed puberty may have positive anti-neutrophil cythoplasmic antibodies, which is usually suggestive of inflammatory bowel disease (IBD) as underlying cause. | |||
=== Hormonal laboratory tests === | |||
==== Luteinizing hormone (LH) ==== | |||
* It is measured on the morning, using immunochemiluminometric (ICMA) or immunofluorometric (IFMA) assays. These tests lower limit of detection is at or below 0.1 IU/liter. | |||
* When the LH level is very low, ICMA measures would be at least half of the IFMA measures.<ref name="pmid17284632">{{cite journal |vauthors=Resende EA, Lara BH, Reis JD, Ferreira BP, Pereira GA, Borges MF |title=Assessment of basal and gonadotropin-releasing hormone-stimulated gonadotropins by immunochemiluminometric and immunofluorometric assays in normal children |journal=J. Clin. Endocrinol. Metab. |volume=92 |issue=4 |pages=1424–9 |year=2007 |pmid=17284632 |doi=10.1210/jc.2006-1569 |url=}}</ref> | |||
* LH more than 0.6 by IFMA or 0.2 by ICMA shows central puberty initiation (high specificity, low sensitivity). If sexual characteristics are not shown up it may show primary hypogonadism.<ref name="pmid17284632" /> | |||
* Generally, LH is better marker for puberty initiation , while FSH is better marker for gonadal failure.<ref name="PalmertDunkel2012">{{cite journal|last1=Palmert|first1=Mark R.|last2=Dunkel|first2=Leo|title=Delayed Puberty|journal=New England Journal of Medicine|volume=366|issue=5|year=2012|pages=443–453|issn=0028-4793|doi=10.1056/NEJMcp1109290}}</ref> | |||
==== Follicle stimulating hormone (FSH) ==== | |||
* It is measured on the morning, using immunochemiluminometric (ICMA) or immunofluorometric (IFMA) assays. These tests lower limit of detection is at or below 0.1 IU/liter. | |||
* When the FSH level is very low, ICMA measures would be at least half of the IFMA measures.<ref name="pmid17284632" /> | |||
* FSH less than 0.2 by ICMA or 0.1 IU/liter by IFMA reflect hypogonadotropic hypogonadism, not diagnostic.<ref name="pmid20371659">{{cite journal |vauthors=Grinspon RP, Ropelato MG, Gottlieb S, Keselman A, Martínez A, Ballerini MG, Domené HM, Rey RA |title=Basal follicle-stimulating hormone and peak gonadotropin levels after gonadotropin-releasing hormone infusion show high diagnostic accuracy in boys with suspicion of hypogonadotropic hypogonadism |journal=J. Clin. Endocrinol. Metab. |volume=95 |issue=6 |pages=2811–8 |year=2010 |pmid=20371659 |doi=10.1210/jc.2009-2732 |url=}}</ref> | |||
* Some patients with delayed puberty may have above normal FSH level, which is usually suggestive of inhibin B deficiency and of primary gonadal failure as underlying cause (high sensitivity, high specificity). | |||
==== Insulin like growth factor (IGF-1) ==== | |||
* It has to measured within 2 hours of sampling, to avoid false increase. The tests that measure the IGF-1 without IGF binding proteins interpretation are favorable only. | |||
* IGF-1 is a reflector of GH serum level. When it is elevated, before or after treatment, it is assumed as less probability of GH deficiency as underlying cause of delayed puberty. | |||
* When GH deficiency is suspected, GH provocation testes are necessary to approve the diagnosis.<ref name="ImranPelkey2010">{{cite journal|last1=Imran|first1=Syed Ali|last2=Pelkey|first2=Michael|last3=Clarke|first3=David B.|last4=Clayton|first4=Dale|last5=Trainer|first5=Peter|last6=Ezzat|first6=Shereen|title=Spuriously Elevated Serum IGF-1 in Adult Individuals with Delayed Puberty: A Diagnostic Pitfall|journal=International Journal of Endocrinology|volume=2010|year=2010|pages=1–4|issn=1687-8337|doi=10.1155/2010/370692}}</ref> | |||
==== Testosterone ==== | |||
* It is measured on the morning. The tests lower limit of detection is at or below 10 ng/liter (0.35 nm/L). The testosterone level has diurnal variation. | |||
* Morning serum level of equal or more than 20 ng/dL (0.7 nmol/L) is showing that the secondary sexual characteristics will be presented in 12 to 15 months.<ref name="pmid8421096">{{cite journal |vauthors=Wu FC, Brown DC, Butler GE, Stirling HF, Kelnar CJ |title=Early morning plasma testosterone is an accurate predictor of imminent pubertal development in prepubertal boys |journal=J. Clin. Endocrinol. Metab. |volume=76 |issue=1 |pages=26–31 |year=1993 |pmid=8421096 |doi=10.1210/jcem.76.1.8421096 |url=}}</ref> | |||
==== Gonadotropin releasing hormone (GnRH) ==== | |||
* It is measured on any times of day. | |||
* Very high serum levels of LH (5-8 IU/liter) or dramatic LH response (compare to FSH) to GnRH stimulation test are suggestive of puberty onset.<ref name="pmid17284632" /> | |||
* LH value of less than 0.8 IU/liter or FSH value of less than 1.1 IU/liter, by IFMA after GnRH, are more reflective of hypogonadotropic hypogonadism in boys.<ref name="pmid17284632" /> | |||
==== Human chorionic gonadotropin (hCG) test ==== | |||
* It is consist of daily intramuscular or subcutaneous injections of hCG. | |||
* The peak concentration of testosterone to both 3-day and 19-day tests is much lower in hypogonadotropic hypogonadism in contrast with CDGP.<ref name="PalmertDunkel2012" /> | |||
* If the GnRH test (peak LH of 2.8 IU/liter) and hCG test (peak testosterone in 19-day test of 275 ng/dL (9.5 nmol/liter)) combined with each other, the sensitivity and specificity are became 100%.<ref name="pmid19017752">{{cite journal |vauthors=Segal TY, Mehta A, Anazodo A, Hindmarsh PC, Dattani MT |title=Role of gonadotropin-releasing hormone and human chorionic gonadotropin stimulation tests in differentiating patients with hypogonadotropic hypogonadism from those with constitutional delay of growth and puberty |journal=J. Clin. Endocrinol. Metab. |volume=94 |issue=3 |pages=780–5 |year=2009 |pmid=19017752 |doi=10.1210/jc.2008-0302 |url=}}</ref> | |||
==== Inhibin B ==== | |||
* It is measured on any times of day. | |||
* An elevated baseline inhibin B in boys is diagnostic of CDGP. Plasma level of more than 35 pg/ml in prepubertal boys present 100% of both sensitivity and specificity, for CDGP.<ref name="pmid20826577">{{cite journal |vauthors=Coutant R, Biette-Demeneix E, Bouvattier C, Bouhours-Nouet N, Gatelais F, Dufresne S, Rouleau S, Lahlou N |title=Baseline inhibin B and anti-Mullerian hormone measurements for diagnosis of hypogonadotropic hypogonadism (HH) in boys with delayed puberty |journal=J. Clin. Endocrinol. Metab. |volume=95 |issue=12 |pages=5225–32 |year=2010 |pmid=20826577 |doi=10.1210/jc.2010-1535 |url=}}</ref> | |||
* Plasma level of more than 65 pg/ml in boys with tanner stage 2 genitalia present 80%-86% sensitivity and 88%-92% specificity, for CDGP. | |||
* Lack of inhibin B in boys may reveal primary germinal failure.<ref name="PalmertDunkel2012" /> | |||
==== Prolactin ==== | |||
* There are only few indications. The prolactin level is influenced by stress, exercise, sleep, hypothyroidism, and some medications; all increase the level. | |||
* Some patients with delayed puberty may have elevated concentration of prolactin, which is usually suggestive of hypothalamic-pituitary tumors causing hypogonadotropic hypogonadism, as underlying cause. | |||
* In patients with asymptomatic hyperprolactinemia, it may be necessary to measure the macroplrolactin (inactivate form of prolactin).<ref name="pmid24397058">{{cite journal |vauthors=Ali L, Adeel A |title=Role of basal and provocative serum prolactin in differentiating idiopathic hypogonadotropic hypogonadism and constitutional delayed puberty--a diagnostic dilemma |journal=J Ayub Med Coll Abbottabad |volume=24 |issue=2 |pages=73–6 |year=2012 |pmid=24397058 |doi= |url=}}</ref> | |||
==== Growth hormone (GH) ==== | |||
* It is measured on any times of day. | |||
* A reduced concentration of gowth hormone (GH) is diagnostic of GH deficiency, as underlying cause of delayed puberty. | |||
{{Family tree/start}} | {{Family tree/start}} | ||
Revision as of 16:50, 8 September 2017
|
Delayed puberty Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Case Studies |
|
Delayed puberty laboratory findings On the Web |
|
American Roentgen Ray Society Images of Delayed puberty laboratory findings |
|
Risk calculators and risk factors for Delayed puberty laboratory findings |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:
Overview
An elevated/reduced concentration of serum/blood/urinary/CSF/other [lab test] is diagnostic of [disease name].
OR
Laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].
OR
[Test] is usually normal among patients with [disease name].
OR
Some patients with [disease name] may have elevated/reduced concentration of [test], which is usually suggestive of [progression/complication].
OR
There are no diagnostic laboratory findings associated with [disease name].
Laboratory Findings
Biochemistry laboratory tests
- In order to evaluating any other underlying diseases, many biochemistry lab tests could be considered. These lab tests are including complete blood count, erythrocyte sedimentation rate, creatinine, electrolytes, bicarbonate, alkaline phosphatase, albumin, thyrotropin, and free thyroxine.
- In case of specific familial disorders, some especial lab tests may be needed, indeed. These lab tests are including anti-gliadin antibody and anti-tissue transglutaminase antibody (i.e., celiac disease diagnosis) or anti-neutrophil cythoplasmic antibodies (i.e., inflammatory bowel disease diagnosis).
Complete blood count
Some patients with delayed puberty may have reduced concentration of hemoglobin, which is usually suggestive of anemia as underlying cause.
Some patients with delayed puberty may have elevated number of lymphocytes, which is usually suggestive of viral infections (mumps, coxsackie) as underlying cause.
Decreasing number of lymphocytes (especially CD4s) may reveal AIDS, as underlying cause of delayed puberty.
Erythrocyte sedimentation rate
An elevated erythrocyte sedimentation rate (ESR) is diagnostic of most of the underlying diseases that may cause delayed puberty.
Creatinine
Some patients with delayed puberty may have elevated concentration of creatinine, which is usually suggestive of renal disease as underlying cause.
Electrolytes
Some patients with delayed puberty may have elevated serum sodium, potassium, or any other electrolytes, which is usually suggestive of renal disease as underlying cause.
Increasing calcium and magnesium may reflect the effect of radiation or chemotherapy as the cause of delayed puberty.
Bicarbonate
Reduced Bicarbonate concentration in serum may reveal the metabolic acidosis due to various causes, mostly chronic kidney injury, as underlying cause of delayed puberty.
Alkaline phosphatase
An elevated/reduced concentration of serum alkaline phosphatase is diagnostic of any liver or bone diseases, as underlying cause of delayed puberty.
Histiocytosis, galactosemia induced hepatomgaly, and Gaucher's diseases are some of examples.
Albumin
Some patients with delayed puberty may have reduced concentration of serum albumin, which is usually suggestive of liver or renal disease as underlying cause.
Thyrotropin
An elevated concentration of serum thyroid stimulating hormone (TSH) is diagnostic of hypothyroidism, as underlying cause of delayed puberty.
Free thyroxine
An reduced concentration of serum free thyroxine (T4) is diagnostic of hypothyroidism, as underlying cause of delayed puberty.
Anti-gliadin antibody
Some patients with delayed puberty may have positive anti gliadin antibody, which is usually suggestive of Celiac disease as underlying cause.
Anti-tissue transglutaminase antibody
Some patients with delayed puberty may have positive anti tissue transglutaminase antibody, which is usually suggestive of Celiac disease as underlying cause.
Anti-neutrophil cythoplasmic antibodies
Some patients with delayed puberty may have positive anti-neutrophil cythoplasmic antibodies, which is usually suggestive of inflammatory bowel disease (IBD) as underlying cause.
Hormonal laboratory tests
Luteinizing hormone (LH)
- It is measured on the morning, using immunochemiluminometric (ICMA) or immunofluorometric (IFMA) assays. These tests lower limit of detection is at or below 0.1 IU/liter.
- When the LH level is very low, ICMA measures would be at least half of the IFMA measures.[1]
- LH more than 0.6 by IFMA or 0.2 by ICMA shows central puberty initiation (high specificity, low sensitivity). If sexual characteristics are not shown up it may show primary hypogonadism.[1]
- Generally, LH is better marker for puberty initiation , while FSH is better marker for gonadal failure.[2]
Follicle stimulating hormone (FSH)
- It is measured on the morning, using immunochemiluminometric (ICMA) or immunofluorometric (IFMA) assays. These tests lower limit of detection is at or below 0.1 IU/liter.
- When the FSH level is very low, ICMA measures would be at least half of the IFMA measures.[1]
- FSH less than 0.2 by ICMA or 0.1 IU/liter by IFMA reflect hypogonadotropic hypogonadism, not diagnostic.[3]
- Some patients with delayed puberty may have above normal FSH level, which is usually suggestive of inhibin B deficiency and of primary gonadal failure as underlying cause (high sensitivity, high specificity).
Insulin like growth factor (IGF-1)
- It has to measured within 2 hours of sampling, to avoid false increase. The tests that measure the IGF-1 without IGF binding proteins interpretation are favorable only.
- IGF-1 is a reflector of GH serum level. When it is elevated, before or after treatment, it is assumed as less probability of GH deficiency as underlying cause of delayed puberty.
- When GH deficiency is suspected, GH provocation testes are necessary to approve the diagnosis.[4]
Testosterone
- It is measured on the morning. The tests lower limit of detection is at or below 10 ng/liter (0.35 nm/L). The testosterone level has diurnal variation.
- Morning serum level of equal or more than 20 ng/dL (0.7 nmol/L) is showing that the secondary sexual characteristics will be presented in 12 to 15 months.[5]
Gonadotropin releasing hormone (GnRH)
- It is measured on any times of day.
- Very high serum levels of LH (5-8 IU/liter) or dramatic LH response (compare to FSH) to GnRH stimulation test are suggestive of puberty onset.[1]
- LH value of less than 0.8 IU/liter or FSH value of less than 1.1 IU/liter, by IFMA after GnRH, are more reflective of hypogonadotropic hypogonadism in boys.[1]
Human chorionic gonadotropin (hCG) test
- It is consist of daily intramuscular or subcutaneous injections of hCG.
- The peak concentration of testosterone to both 3-day and 19-day tests is much lower in hypogonadotropic hypogonadism in contrast with CDGP.[2]
- If the GnRH test (peak LH of 2.8 IU/liter) and hCG test (peak testosterone in 19-day test of 275 ng/dL (9.5 nmol/liter)) combined with each other, the sensitivity and specificity are became 100%.[6]
Inhibin B
- It is measured on any times of day.
- An elevated baseline inhibin B in boys is diagnostic of CDGP. Plasma level of more than 35 pg/ml in prepubertal boys present 100% of both sensitivity and specificity, for CDGP.[7]
- Plasma level of more than 65 pg/ml in boys with tanner stage 2 genitalia present 80%-86% sensitivity and 88%-92% specificity, for CDGP.
- Lack of inhibin B in boys may reveal primary germinal failure.[2]
Prolactin
- There are only few indications. The prolactin level is influenced by stress, exercise, sleep, hypothyroidism, and some medications; all increase the level.
- Some patients with delayed puberty may have elevated concentration of prolactin, which is usually suggestive of hypothalamic-pituitary tumors causing hypogonadotropic hypogonadism, as underlying cause.
- In patients with asymptomatic hyperprolactinemia, it may be necessary to measure the macroplrolactin (inactivate form of prolactin).[8]
Growth hormone (GH)
- It is measured on any times of day.
- A reduced concentration of gowth hormone (GH) is diagnostic of GH deficiency, as underlying cause of delayed puberty.
| Delayed puberty | |||||||||||||||||||||||||||||||||||||||||||||||
| Clinical suspicion to delayed puberty (Absent growth spurt along with lack of testicular enlargement or breast development) | |||||||||||||||||||||||||||||||||||||||||||||||
| First line evaluation • Biochemical analyses • Bone age radiography • Basal serum LH, FSH, IGF-1, TSH, free thyroxine, and testosterone (in boys) | |||||||||||||||||||||||||||||||||||||||||||||||
| Reduced or normal LH and FSH | Elevated FSH or LH | ||||||||||||||||||||||||||||||||||||||||||||||
| Growth rate as prepubertal | Growth rate lower than prepubertal | ||||||||||||||||||||||||||||||||||||||||||||||
| Constitutional delay of growth and puberty (CDGP) | Gonadotropin releasing hormone (GnRH) deficiency | Transient hypogonadotropic hypogonadism | Permanent hypogonadotropic hypogonadism | Hypergonadotropic hypogonadism | |||||||||||||||||||||||||||||||||||||||||||
| Second line evaluation | Second line evaluation | Second line evaluation | |||||||||||||||||||||||||||||||||||||||||||||
| • GnRH test • hCG stimulation test • Serum inhibin B • Olfactory-function test • Genetic testing • MRI | Evaluating more underlying diseases: • MRI • Prolactin | Evaluating more underlying diseases: • Karyotype • Serum inhibin B | |||||||||||||||||||||||||||||||||||||||||||||
| Low BMI | Normal BMI | High BMI | |||||||||||||||||||||||||||||||||||||||||||||
| • GI disorder • Malnutrition • Anorexia | • Hypothyreosis • Hyperprolactinemia • Multiple pituitary hormone deficiency | • Glucocorticoid excess (iatrogenic, Cushing’s disease) • Hypothyroidism | |||||||||||||||||||||||||||||||||||||||||||||
| Follow up Evaluate the need for the induction of secondary sex characteristics | Treat underlying disease | Treat with sex steroids | |||||||||||||||||||||||||||||||||||||||||||||
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Resende EA, Lara BH, Reis JD, Ferreira BP, Pereira GA, Borges MF (2007). "Assessment of basal and gonadotropin-releasing hormone-stimulated gonadotropins by immunochemiluminometric and immunofluorometric assays in normal children". J. Clin. Endocrinol. Metab. 92 (4): 1424–9. doi:10.1210/jc.2006-1569. PMID 17284632.
- ↑ 2.0 2.1 2.2 Palmert, Mark R.; Dunkel, Leo (2012). "Delayed Puberty". New England Journal of Medicine. 366 (5): 443–453. doi:10.1056/NEJMcp1109290. ISSN 0028-4793.
- ↑ Grinspon RP, Ropelato MG, Gottlieb S, Keselman A, Martínez A, Ballerini MG, Domené HM, Rey RA (2010). "Basal follicle-stimulating hormone and peak gonadotropin levels after gonadotropin-releasing hormone infusion show high diagnostic accuracy in boys with suspicion of hypogonadotropic hypogonadism". J. Clin. Endocrinol. Metab. 95 (6): 2811–8. doi:10.1210/jc.2009-2732. PMID 20371659.
- ↑ Imran, Syed Ali; Pelkey, Michael; Clarke, David B.; Clayton, Dale; Trainer, Peter; Ezzat, Shereen (2010). "Spuriously Elevated Serum IGF-1 in Adult Individuals with Delayed Puberty: A Diagnostic Pitfall". International Journal of Endocrinology. 2010: 1–4. doi:10.1155/2010/370692. ISSN 1687-8337.
- ↑ Wu FC, Brown DC, Butler GE, Stirling HF, Kelnar CJ (1993). "Early morning plasma testosterone is an accurate predictor of imminent pubertal development in prepubertal boys". J. Clin. Endocrinol. Metab. 76 (1): 26–31. doi:10.1210/jcem.76.1.8421096. PMID 8421096.
- ↑ Segal TY, Mehta A, Anazodo A, Hindmarsh PC, Dattani MT (2009). "Role of gonadotropin-releasing hormone and human chorionic gonadotropin stimulation tests in differentiating patients with hypogonadotropic hypogonadism from those with constitutional delay of growth and puberty". J. Clin. Endocrinol. Metab. 94 (3): 780–5. doi:10.1210/jc.2008-0302. PMID 19017752.
- ↑ Coutant R, Biette-Demeneix E, Bouvattier C, Bouhours-Nouet N, Gatelais F, Dufresne S, Rouleau S, Lahlou N (2010). "Baseline inhibin B and anti-Mullerian hormone measurements for diagnosis of hypogonadotropic hypogonadism (HH) in boys with delayed puberty". J. Clin. Endocrinol. Metab. 95 (12): 5225–32. doi:10.1210/jc.2010-1535. PMID 20826577.
- ↑ Ali L, Adeel A (2012). "Role of basal and provocative serum prolactin in differentiating idiopathic hypogonadotropic hypogonadism and constitutional delayed puberty--a diagnostic dilemma". J Ayub Med Coll Abbottabad. 24 (2): 73–6. PMID 24397058.