BackWhat is measurement uncertainty?
There is no such thing as a perfectly accurate measurement. When we measure something, the result depends on the measurement system, the measurement method, the experience of the personnel, the environmental conditions and other parameters. Even if we make several measurements using the same technique and under the same conditions, we will get slightly different results each time (provided that the resolution of the instrument allows us to notice this difference). The values recorded in each measurement can be considered as individual measurement results that fall within a certain range of values (coefficient of variation, CV, %). Below is a table with the measurement uncertainty of quantitative tests in our laboratory. For example, a Total Protein result of 80 g/L, with an uncertainty of ±2.5 % we get a range of 78 to 82 g/L. This does not mean that 80 g/L test result is inaccurate, the uncertainty range sets limits on the overall uncertainty of the test result.
Measurement uncertainty of quantitative tests
|
№ |
Test |
Unit of measurement |
Uncertainty of measurements, CV, % |
|
1. |
Alanine aminotransferase (ALT) |
U/l |
2,3 |
|
2. |
Aspartate aminotransferase (АSТ) |
U/l |
3,3 |
|
3. |
Alkaline phosphatase (ALP) |
U/l |
2,1 |
|
4. |
Gammaglutamyltransferase (GGTF) |
U/l |
3,7 |
|
5. |
Lactic dehydrogenase (LDG) |
U/l |
2,7 |
|
6. |
Lactate |
mmol/l |
1,6 |
|
7. |
α-amylase (diastasis) |
U/l |
2,4 |
|
8. |
Рancreatic amylase |
U/l |
2,1 |
|
9. |
Lipase |
U/l |
2,1 |
|
10. |
Creatine kinase (CPK) |
U/l |
3,3 |
|
11. |
Total protein |
g/l |
2,5 |
|
12. |
Albumin |
g/l |
1,0 |
|
13. |
Total bilirubin |
mcmol/l |
4,5 |
|
14. |
Direct bilirubin |
mcmol/l |
4,7 |
|
15. |
Uric acid |
mcmol/l |
1,3 |
|
16. |
Ureal |
mmol/l |
1,3 |
|
17. |
Creatinine |
mcmol/l |
5,0 |
|
18. |
Glucose (blood sugar) |
mmol/l |
1,0 |
|
19. |
Glycosylated hemoglobin |
% |
2,0 |
|
20. |
Triglycerides |
mmol/l |
1,9 |
|
21. |
Total cholesterol |
mmol/l |
1,6 |
|
22. |
HDL cholesterol |
mmol/l |
0,9 |
|
23. |
LDL cholesterol |
mmol/l |
2,1 |
|
24. |
Apolipoprotein A1 |
g/l |
3,6 |
|
25. |
Apolipoprotein B |
g/l |
2,9 |
|
26. |
Total calcium (Са) |
mmol/l |
1,3 |
|
27. |
Magnesium (Мg) |
mmol/l |
1,1 |
|
28. |
Inorganic phosphorus |
mmol/l |
1,4 |
|
29. |
Natrium (Na+) |
mmol/l |
0,34 |
|
30. |
Kalium (K+) |
|
1,13 |
|
31. |
Calcium (Ca2+) ionised |
|
3,29 |
|
32. |
Ferrum (Fe) |
mcmol/l |
1,8 |
|
33. |
Transferrin |
g/l |
2,6 |
|
34. |
Ferritin |
ng/ml |
2,8 |
|
35. |
Cerulloplasmin (copper metabolism) |
g/l |
2,6 |
|
36. |
Latent iron binding capacity |
mcmol/l |
4,7 |
|
37. |
Vit B 12 |
pg/ml |
8,4 |
|
38. |
Folic acid |
ng/ml |
8,2 |
|
39. |
IgA (immunoglobulin A) |
g/l |
1,8 |
|
40. |
IgM (immunoglobulin М) |
g/l |
2,8 |
|
41. |
IgG immunoglobulin G) |
g/l |
1,7 |
|
42. |
IgЕ (immunoglobulin Е) |
IU/ml |
3,4 |
|
43. |
C-reactive protein |
mg/l |
2,5 |
|
44. |
C-reactive protein Cardio (high-sensitivity) |
mg/dl |
8,4 |
|
45. |
C3 complement component |
g/l |
2,0 |
|
46. |
C4 complement component |
g/l |
1,8 |
|
47. |
Rheumatoid factor (RF) |
IU/ml |
1,8 |
|
48. |
Antibodies to cyclic citrullinated peptide (ACCP, anti-CCP, marker of Rheumatoid Arthritis) |
IU/ml |
1,9 |
|
49. |
Antistreptolysin O (ASLO) |
IU/mL |
2,5 |
|
50. |
TSH (thyroid hormone) ultrasensitive |
mcIU/mL |
7,2 |
|
51. |
T3 (triiodothyronine) total |
nmol/l |
4,5 |
|
52. |
T4 (thyroxine) total |
mcg/dL |
4,2 |
|
53. |
T3 (triiodothyronine) free |
pg/ml |
3,4 |
|
54. |
T4 (thyroxine) free |
ng/dl |
3,6 |
|
55. |
Anti-TG (antibodies to thyroglobulin) |
IU/ml |
6,3 |
|
56. |
Antibodies to TSH receptors |
IU/ml |
11,4 |
|
57. |
Anti-TPO (antibodies to microsomal thyroperoxidase) |
IU/ml |
9,5 |
|
58. |
Parathormone |
pg/ml |
3,4 |
|
59. |
FSH (follicle stimulating hormone) |
mlU/ml |
4,5 |
|
60. |
LH (luteinising hormone). |
mlU/ml |
2,2 |
|
61. |
HCG (human chorionic gonadotrophin) |
mlU/ml |
4,6 |
|
62. |
Prolactin |
ng/ml |
1,8 |
|
63. |
Estradiol |
pg/ml |
4,7 |
|
64. |
Progesterone |
ng/ml |
4,8 |
|
65. |
Testosterone |
ng/ml |
5,6 |
|
66. |
Sex hormone-binding globulin (SHBG, Sex hormone-binding globulin) Free testosterone index is calculated free of charge if Testosterone and SHBG are ordered at the same time |
nmol/l |
4,0 |
|
67. |
DHEA-sulphate (dehydroepiandrosterone sulphate) |
mcg/dl |
2,7 |
|
68. |
ACTH (adrenocorticotropic hormone) |
pmol/l |
5,4 |
|
69. |
Сortisol |
nmol/l |
2,8 |
|
70. |
Insulin |
mcME/ml |
4,9 |
|
71. |
C-Peptide |
ng/ml |
2,3 |
|
72. |
Chondrotropic hormone (Somatotropin, STH, Growth hormone, GH) |
ng/ml |
3,4 |
|
73. |
AFP - alpha-fetoprotein (liver, ovaries) |
ng/ml |
3,8 |
|
74. |
СEA (intestine) |
ng/ml |
5,0 |
|
75. |
CA 19-9 antigen (stomach, pancreas) |
U/ml |
8,0 |
|
76. |
CA 125 antigen (ovaries) |
U/ml |
2,5 |
|
77. |
PSA (prostate-specific antigen) total (sensitive) |
ng/ml |
3,7 |
|
78. |
PSA (prostate-specific antigen) free |
ng/ml |
4,9 |
|
79. |
CA 72-4 antigen (stomach, ovaries) |
U/ml |
3,6 |
|
80. |
CA 15-3 antigen (breast) |
U/ml |
5,0 |
|
81. |
Thyroglobulin (thyroid gland) |
ng/ml |
3,6 |
|
82. |
CYFRA (lungs, bladder) |
ng/ml |
2,7 |
|
83. |
Neuron-specific enolase (central and peripheral nervous system, lung, endocrine system) |
ng/ml |
3,8 |
|
84. |
Beta-Cross laps |
ng/ml |
8,4 |
|
85. |
Osteocalcin |
ng/ml |
2,3 |
|
86. |
Procalcitonin (PCT) |
ng/ml |
8,7 |
|
87. |
Natriuretic hormone (B-type) N-terminal propeptide (NT-proBNP, N-terminal pro-brain natriuretic peptide, pro-B-type natriuretic peptide) |
pg/ml |
3,1 |
|
88. |
Acidum Valproicum (Acidum Valproicum, Depakine, Convulex) |
mcg/ml |
3,9 |
|
89. |
Anti-Rub IgG (IgG class antibodies to rubella virus) |
IU/ml |
3,3 |
|
90. |
Anti-Toxo IgG (IgG class antibodies to Toxoplasma gondii) |
IU/ml |
5,3 |
|
91. |
Anti-CMV-IgG (Cytomegalovirus IgG antibodies) |
IU/ml |
4,5 |
|
92. |
Fibrinogen |
g/l |
4,2 |
|
93. |
APPT |
sec. |
as 1,1 |
|
94. |
TT |
sec. |
5,1 |
|
95. |
Prothrombin time |
sec. |
3,0 |
|
96. |
Allergy tests |
IU/ml |
12,0 |
|
97. |
Hemoglobin (HGB) |
g/l |
1,5 |
|
98. |
Plasma cells |
% |
7,0 |
|
99. |
Lymphocytes (LYM) |
% |
3,0 |
|
100. |
Monocytes (MON) |
% |
2,0 |
|
101. |
Basophils (BAS) |
% |
0,8 |
|
102. |
Eosinophils (EOS) |
% |
1,5 |
|
103. |
Segmentonuclear (NEU) |
% |
5,0 |
|
104. |
White blood cells (WBC) |
109/l |
3,0 |
|
105. |
Mean platelet volume (MPV) |
fL |
2,0 |
|
106. |
Thrombocrit (PCT) |
% |
1,3 |
|
107. |
Platelets (PLT) |
109/l |
4,0 |
|
108. |
Hemoglobin distribution width (HDW) |
g/l |
1,0 |
|
109. |
Red blood cell distribution width (RDW) |
% |
2,5 |
|
110. |
Mean Hb concentration in a red blood cell (MCHC) |
g/l |
2,8 |
|
111. |
Mean Hb content in a red blood cell (MCH) |
pg |
1,6 |
|
112. |
Mean red blood cell volume (MCV) |
fL |
1,5 |
|
113. |
Haematocrit (HCT) |
% |
1,3 |
|
114. |
Red blood cells (RBC) |
1012/l |
1,5 |
|
115. |
Albumin (electrophoresis) |
% |
0,7 |
|
116. |
Alpha 1-globulins (electrophoresis) |
% |
3,1 |
|
117. |
Alpha 2-globulins (electrophoresis) |
% |
1,4 |
|
118. |
Beta 1-globulins (electrophoresis) |
% |
1,9 |
|
119. |
Beta 2-globulins (electrophoresis) |
% |
2,4 |
|
120. |
Gamma-globulins (electrophoresis) |
% |
1,4 |