| Eckfeldt J,Chambless Ll and Shen Y, 1994, Arch Pathol Lab Med, 118, 496-500 | 9.5 | 1.1 | Mixed | Healthy (excl pregnant) | Serum |
| Hölzel WGE, 1987, Clin Chem, 33, 57-61 | 11.3 | | Females | Healthy (excl pregnant) | Serum |
| Gowans EMS, Fraser G., 1987, Clin Chem, 33, 717 | 13.9 | 13.8 | Mixed | Healthy (excl pregnant) | Serum |
| Nunes LA, Brenzikofer R and Vaz de Macedo D, 2010, Eur J Appl Physiol, 110, 191-8 | 14.4 | 20.0 | Males | Healthy (excl pregnant) | Serum |
| Costongs GMPJ, Janson PCW and Bas BM, 1985, J Clin Chem Clin Biochem, 23, 7-16 | 11.2 | | Mixed | Healthy (excl pregnant) | Serum |
| Aarsand AK, Diaz-Garzón J, Fernández-Calle P, et al, 2018, Clin Chem, 64(9), 1380-93 | 14.1 | 22.5 | Mixed | Healthy (excl pregnant) | Serum |
| Hölzel WGE, 1987, Clin Chem, 33, 57-61 | 9.5 | | Males | Healthy (excl pregnant) | Serum |
| Harris EK, Kanofsky P, Shakarji G and Cotlove E, 1970, Clin Chem, 16, 1022-7 | 11.9 | | Mixed | Healthy (excl pregnant) | Serum |
| Young DS, Harris EK and Cotlove E, 1971, Clin Chem, 17, 403-10 | 13.6 | 13.4 | Males | Healthy (excl pregnant) | Serum |
| Pineda-Tenor D , Laserna-Mendieta EJ, Timon-Zapata J, Rodelgo-Jimenez L, Ramos-Corral R, Recio-Montealegre A and Gomez-Serranillos Reus M, 2013, Clin Chem Lab Med, 51, 851-62 | 10.9 | 18.3 | Males | Healthy (excl pregnant) | Serum |
| Pineda-Tenor D , Laserna-Mendieta EJ, Timon-Zapata J, Rodelgo-Jimenez L, Ramos-Corral R, Recio-Montealegre A and Gomez-Serranillos Reus M, 2013, Clin Chem Lab Med, 51, 851-62 | 12.1 | 19.6 | Females | Healthy (excl pregnant) | Serum |
| Loh TP and Metz MP, 2015, Am J Clin Pathol, 143, 683-93 | 12.5 | 27.3 | Males | Healthy (excl pregnant) | Serum |
| Loh TP and Metz MP, 2015, Am J Clin Pathol, 143, 683-93 | 12.4 | 28.8 | Females | Healthy (excl pregnant) | Serum |
| Lacher DA, Hughes JP and Carroll MD, 2010, National Health Statistics Reports , 21, | 17.9 | 32.4 | Mixed | Healthy (excl pregnant) | Serum |
| Qi Z, Chen Y, Zhang L, Ma X, Wang F, Cheng Q, Du J, Hao Y, Chi S, Cui W, 2016, Clin Chim Acta, 452, 87-91 | 8.3 | 11.2 | Females | Healthy (excl pregnant) | Plasma |
| Qi Z, Chen Y, Zhang L, Ma X, Wang F, Cheng Q, Du J, Hao Y, Chi S, Cui W, 2016, Clin Chim Acta, 452, 87-91 | 5.1 | 14.2 | Males | Healthy (excl pregnant) | Plasma |
| Cotlove E, Harris EK and Williams GZ, 1970, Clin Chem, 16, 1028-32 | 15.5 | 24.0 | Mixed | Healthy (excl pregnant) | Serum |
| Dimitri G, Bolner A and Gheller A, 1992, Biochim Clin, 16, 401-3 | 10.8 | | Mixed | Healthy (excl pregnant) | Serum |
| Chitto G, Fabi A, Franzini C, Galletta G, Leonardi A, Marelli M and Morelli AM, 1994, Biochim Clin, 18, 673-690 | 11.0 | | Mixed | Healthy (excl pregnant) | Serum |
| Aarsand AK, Diaz-Garzón J, Fernández-Calle P, et al, 2018, Clin Chem, 64(9), 1380-93 | 12.5 | 19.4 | Males | Healthy (excl pregnant) | Serum |
| Aarsand AK, Diaz-Garzón J, Fernández-Calle P, et al, 2018, Clin Chem, 64(9), 1380-93 | 12.9 | 15.9 | Females | Healthy (excl pregnant) | Serum |
| Winkel P, Statland BE and Bokelund H, 1974, Clin Chem, 20, 1520-7 | 11.5 | 16.4 | Males | Healthy (excl pregnant) | Serum |
| Winkel P and Statland BE, 1976, Clin Chem, 22, 1855-61 | 5.0 | | Females | Healthy (excl pregnant) | Serum |
| Fraser CG and Williams P, 1983, Clin Chem, 29, 508-10 | 6.5 | 56.7 | Males | Non-healthy (excl pregnant) | Plasma |
| Aarsand AK, Diaz-Garzón J, Fernández-Calle P, et al, 2018, Clin Chem, 64(9), 1380-93 | 15.7 | 19.7 | Females | Healthy (excl pregnant) | Serum |
| Fraser CG and Hearne CR, 1982, Ann Clin Biochem, 19, 431-4 | 18.3 | 27.2 | Males | Healthy (excl pregnant) | Plasma |
| Biosca C, Ricós C, Jiménez CV, Lauzurica R and Galimany R, 1997, Clin Chem, 43, 2206-8 | 13.9 | 21.1 | Mixed | Non-healthy (excl pregnant) | Serum |
| Fraser CG., Cummings ST., Wilkinson SP., Neville RG., Knox JDE, Ho O and MacWalter RS, 1989, Clin Chem, 35, 783-6 | 1.2 | 13.4 | Mixed | Healthy (excl pregnant) | Serum |
| Pickup JF, Harris EK, Kearns M and Brown SS, 1977, Clin Chem, 23, 842-50 | 11.1 | | Males | Healthy (excl pregnant) | Serum |
| Bailey D, Bevilacqua V, Colantonio DA, Pasic MD, Perumal N, Chan MK and Adeli K, 2014, Clin Chem, 60, 518-29 | 7.5 | 22.1 | Mixed | Healthy (excl pregnant) | Plasma |
| Statland BE, Winkel P and Bokelund H, 1973, Clin Chem, 19, 1374-9 | 4.9 | 52.4 | Males | Healthy (excl pregnant) | Serum |
| Pineda-Tenor D , Laserna-Mendieta EJ, Timon-Zapata J, Rodelgo-Jimenez L, Ramos-Corral R, Recio-Montealegre A and Gomez-Serranillos Reus M, 2013, Clin Chem Lab Med, 51, 851-62 | 12.6 | 18.8 | Males | Healthy (excl pregnant) | Serum |
| Pineda-Tenor D , Laserna-Mendieta EJ, Timon-Zapata J, Rodelgo-Jimenez L, Ramos-Corral R, Recio-Montealegre A and Gomez-Serranillos Reus M, 2013, Clin Chem Lab Med, 51, 851-62 | 14.7 | 20.1 | Females | Healthy (excl pregnant) | Serum |
