Bajaña, Aranda, Arredondo, Brennan-Bourdon, Campelo, Espinoza, Flores, Ochoa, Vega, Varela, and Lima-Oliveira: Impact of an Andean breakfast on biochemistry and immunochemistry laboratory tests: an evaluation on behalf COLABIOCLI WG-PRE-LATAM

Introduction

The Andean countries are a group of South American nations that geographically comprise Venezuela, Colombia, Ecuador, Peru, Bolivia, northern Argentina and Chile. Agricultural production and livestock farming are the basis of the usual diet in these different countries. Nevertheless, improvement of the means of transport, transculturation due to the movements of the inhabitants, expanded distribution of agricultural products, food, and globalization, have contributed to generating a multicultural Andean diet.

Ecuador has a total area of 283,561 km2 (land + Galapagos Islands). Population is more than 16 million, with the majority living in the central provinces, in the Andes, and near the Pacific ocean coast (1). Economic growth has been the main cause of changes in the Latin American population dietary habits (2). Moreover, patients from Latin America have a particularly lifestyle that could promote changes in hormone levels, such as food intake, the ingestion of local tea infusions, sport practices, and also the altitude. The Andean breakfast in Ecuador include the Bolones, a fried green plantain dumplings typically stuffed with cheese or with chicharrones; briefly, chicharrones in Mexico and Central America are fried pork rinds, whereas, in Ecuador, these are actually chunks of deep fried fatty pork meat.

All the procedures preceding laboratory testing – the preanalytical phase – are responsible for the main source of laboratory variability (3, 4). Fasting time for the majority of blood tests should be 12 h, whereas for lipid profile alone there is an exception based on European consensus (5, 6). Presently, incorrect fasting status can be a source of errors that can jeopardize patient safety (7-9). The Latin American Working Group for Preanalytical Phase (WG-PRE-LATAM) of the Latin America Confederation of Clinical Biochemistry (COLABIOCLI), established in 2017, has the primary goal of studying preanalytical variability and establishing guidelines for preanalytical procedures to be applied by clinical laboratories and healthcare professionals in Latin America. This study on behalf of COLABIOCLI WG-PRE-LATAM was aimed at evaluating whether an Andean breakfast can interfere with routine biochemistry and immunochemistry laboratory tests done in either serum or plasma samples from the same individuals.

Materials and Methods

Study design

A total of 20 healthy volunteers (12 women and 8 men; average age was 32 (21-52) years) were selected from the personnel of the University of Guayaquil (Ecuador) and included in the study. Informed consent was obtained from all study subjects according to the 2013 Declaration of Helsinki and the protocol was approved by the Ethics Committee.

After a 12 hour overnight fast, the first blood sample was collected between 8:00 and 8:30 a.m. Then, immediately after the first venous blood collection, the subjects ate the Andean breakfast, containing standardized amounts of carbohydrates, protein, and lipids. Table 1 shows the exact composition of the Andean breakfast. Subsequent venous blood samples were performed at 1, 2, and 4 hours after breakfast.

Table 1

Nutritional composition of Andean breakfast

Nutritional composition Bolon chicharrón Scrambled eggs Yogurt Apple juice Total
Number
(overall weight, g)
1
(380)
1
(100)
1
(185)
1
(200)
4
(865)
Kcal 506 121 130 70.0 827
KJ 2117 505 545 293 3460
Protein (g) 6.8 12.1 6.0 0.0 24.9
Carbohydrate (g) 20.5 3.45 NA 17.0 41.0
Total lipids (g) 44.8 6.90 4.0 0.0 55.7
Cholesterol (mg) 42.2 448 10.0 0.0 500
NA – not available. Kcal - kilocalorie. KJ – kilojoule. Bolon chicharrón: a fried green plantain dumplings stuffed with chicharrones; briefly chicharrones in Ecuador are chunks of deep fried fatty pork meat.

According to the international EFLM-COLABIOCLI recommendations, all venous blood sampling procedures were carried out by a single phlebotomist (7). In order to eliminate possible blood distribution interferences, all volunteers were kept in an upright sitting position for 15 min (10). Then, a vein was located on the forearm, however, in order to prevent venous stasis interference from the use of the tournique, and thus, avoid clench, a subcutaneous tissue transilluminator device (Venoscópio IV plus; Duan do Brasil, Brazil) was used (11, 12). All blood samples were collected directly into one 3.5 mL evacuated tube containing gel separator and clot activator for serum samples, and into one 3.0 mL evacuated tube containing lithium heparin and gel separator for plasma samples (Vacumed®, FL Medical, Torreglia, Italy) using a 20 gauge needle in a closed evacuated system (FL Medical, Torreglia, Italy). To eliminate any possible interference due to either the contact phase or tissue factor, approximately 2 mL of blood were preliminarily collected in a discard tube without additive. The blood collection procedure was appropriately standardized in each phase, as already reported, particularly, in regard to sample processing, centrifugation and serum/plasma separation (13).

All samples were assayed in a single analytical run in the same instrument according to the manufacturer’s specifications and using proprietary reagents. The panel of tests that were performed and the instruments used by the International Laboratories Services Interlab S.A. (Guayaquil, Ecuador), an accredited laboratory due to International Organization for Standardization (ISO) 15189 standard, are shown in Table 2. The Ecuadorian Accreditation Service informed us that Ecuador has approximately 3900 clinical laboratories (3000 private and 900 public). However, the accreditation process according to ISO 15189 standard started in 2010, and presently, there are only eight accredited laboratories.

Table 2

Results of within-run precision by the internal quality control of the used instruments

Instrument Test Method IQC assigned values CVa (%)
ARCHITECT C8000, ABBOTT CHOL enzymatic, cholesterol oxidase / cholesterol esterase 4.82 mmol/L 0.5
HDL accelerator selective detergent, cholesterol oxidase / cholesterol esterase 0.80 mmol/L 1.7
TG enzymatic, glycerol phosphate oxidase 1.07 mmol/L 0.7
TP biuret 62.5 g/L 0.5
Alb bromocresol green, colorimetric 40.6 g/L 0.3
Urea UV, urease 5.42 mmol/L 1.5
CREA kinetic, alkaline picrate 232 µmol/L 0.9
CRP immunoturbidimetric 4.92 mg/L 0.7
UA enzymatic, uricase 0.33 mmol/L 0.6
ALP p-nitrophenyl phosphate 124 U/L 0.5
AMY CNPG3 substrate 76.7 U/L 1.0
AST IFCC, UV without P5P, 37 °C 34.1 U/L 1.3
ALT IFCC, UV without P5P, 37 °C 34.0 U/L 1.8
GGT L-Gamma-glutamyl-3-carboxy-4-nitroanilide substrate 55.0 U/L 1.1
LD IFCC, UV lactate-pyruvate 220 U/L 1.6
LIP quinone dye 43.0 U/L 0.8
CK N-acetyl-L-cysteine, NAC 137 U/L 1.3
TBIL diazonium salt 17.8 µmol/L 1.0
DBIL diazo reaction 18.6 µmol/L 1.1
Phos UV, phosphomolybdate 1.42 mmol/L 0.6
Ca arsenazo III, colorimetric 2.36 mmol/L 0.6
Mg arsenazo, colorimetric 0.91 mmol/L 1.3
Fe ferene, colorimetric 19.3 µmol/L 1.0
Na ion-selective electrode 143 mmol/L 0.2
K ion-selective electrode 4.00 mmol/L 0.2
Cl ion-selective electrode 99.0 mmol/L 0.2
IMMULITE 2000 XP, Siemens TSH chemiluminescence, biotin–streptavidin based 0.42 mIU/L 3.4
FT4 chemiluminescence, biotin–streptavidin based 12.1 pmol/L 5.6
Cobas e-601, Roche Ins electrochemiluminescence, biotin–streptavidin based 176 mIU/L 1.6
Cortisol electrochemiluminescence, biotin–streptavidin based 94.4 nmol/L 1.7
IQC – internal quality control. CVa – analytical coefficient of variation. CHOL – cholesterol. HDL – high density lipoprotein. TG – triglycerides. TP – total protein. Alb – albumin. CREA – creatinine. CRP – C reactive protein. UA – uric acid. ALP – alkaline phosphatase. AMY – amylase. AST – aspartate aminotransferase. ALT – alanine aminotransferase. GGT – gamma glutamyl transferase. LD – lactate dehydrogenase. LIP – lipase. CK – creatine kinase. TBIL – total bilirubin. DBIL – direct bilirubin. Phos – phosphate. Ca – calcium. Mg – magnesium. Fe – iron. Na – sodium. K – potassium. Cl – chloride. TSH – thyroid stimulating hormone. FT4 – free thyroxin. Ins – insulin.

The instruments were calibrated against appropriate proprietary reference standard materials and verified with independent third-party control materials from calibrator materials (Lyphochek® Level 1 for routine biochemistry tests and Lyphochek Immunoassay Plus Control®, Level 1 for immunochemistry assays, Bio-Rad, California, USA), as recommended (14). The evaluation of the within-run precision by the internal quality control of the instruments used in this study, showed low coefficients of variation (Table 2).

Statistical analysis

For assessing statistical difference between samples, the Wilcoxon ranked-pairs test was used in agreement with Simundic’s recommendations regarding sample size (i.e. less than 30), with a licensed statistical software (GraphPad Prism® version 5.01, La Jolla, CA, USA) (15). The level of statistical significance was set at P < 0.05. Mean % differences were determined according to the formula: mean % difference = [(× h after breakfast − basal) / × h after breakfast] × 100%.

Finally, the mean % differences from blood samples at 1, 2 and 4 hours after breakfast, were compared with the desirable specification for imprecision (DSI) derived from biologic variation (16). DSI was used as our criterion of acceptance in lipemia analytical interference testing, then interferograms were provided for each laboratory parameter with significant difference between basal and x h after Andean breakfast.

Results

The results of the routine biochemistry laboratory tests are presented as median (interquartile range) in Table 3. Among all the results, statistical significant differences between basal and x h after the Andean breakfast were observed for the following parameters: triglycerides (TG), insulin (Ins), cortisol, thyroid stimulating hormone (TSH), free thyroxine (FT4), total protein (TP), albumin (Alb), urea, creatinine (CREA), lactate dehydrogenase (LD), alkaline phosphatase (ALP), amylase (AMY), lipase (LIP), total bilirubin (TBIL), direct bilirubin (DBIL), iron (Fe), calcium (Ca), phosphate (Phos), magnesium (Mg), and uric acid (UA) (Figure 1). In regards to serum vs. plasma (Table 3), both specimen types showed differences mainly related to the same tests, except for UA at 2 h (significant for serum, not for plasma). Moreover, plasma samples showed higher mean values for TP, clearly due to fibrinogen presence as expected. Mean values of serum ALP and AMY were slightly higher than plasma, whereas potassium (K) was significantly lower in plasma than in serum, an effect most probably due to lithium heparin an ion which competes with K for intracellular transport, and formation of coagulum, which is accompanied by extraction of potassium from platelets.

Table 3

Postprandial variation on laboratory tests after Andean breakfast

SERUM PLASMA
Test
(Unit)
BASAL 1h 2h 4h BASAL 1h 2h 4h
CHOL (mmol/L) 5.0
(4.6 - 5.5)
5.0
(4.7 - 5.4)
5.0
(4.8 - 5.4)
5.0
(4.8 - 5.5)
5.0
(4.6 - 5.4)
4.9
(4.6 - 5.3)
5.0
(4.6 - 5.4)
4.9
(4.7 - 5.4)
P - 0.777 0.667 0.720 - 0.856 0.738 0.113
HDL (mmol/L) 1.2
(1.0 - 1.5)
1.2
(1.0 - 1.5)
1.2
(1.0 - 1.4)
1.2
(1.0 - 1.4)
1.2
(1.0 - 1.5)
1.2
(1.1 - 1.5)
1.2
(1.0 - 1.5)
1.2
(1.0 - 1.4)
P - 0.897 0.737 0.528 - 0.764 0.629 0.472
TG
(mmol/L)
1.3
(1.1 - 1.7)
1.7
(1.4 - 2.2)
2.4
(1.5 - 3.1)
2.4
(1.4 - 3.2)
1.2
(1.0 - 1.6)
1.7
(1.3 - 2.1)
2.3
(1.8 - 3.2)
2.3
(1.3 - 3.1)
P - < 0.001 < 0.001 < 0.001 - < 0.001 < 0.001 < 0.001
TP
(g/L)
72
(70 - 78)
73
(71 - 78)
74
(71 - 79)
76
(71 - 78)
75
(72 - 80)
75
(72 - 81)
76
(71 - 80)
78
(72 - 80)
P - 0.033 0.002 0.008 - 0.034 0.005 0.002
Alb
(g/L)
45
(43 - 48)
45
(43 - 48)
45
(43 - 49)
47
(43 - 49)
44
(42 - 47)
45
(42 - 47)
45
(42 - 48)
46
(42 - 48)
P - 0.513 0.081 0.033 - 0.647 0.760 0.021
Urea (mmol/L) 3.7
(3.0 - 4.1)
3.9
(3.2 - 4.4)
4.3
(3.4 - 4.9)
4.5
(4.0 – 5.0)
3.5
(3.0 - 4.2)
3.9
(3.1 - 4.3)
4.1
(3.5 - 4.7)
4.4
(3.7 - 4.9)
P - 0.001 0.001 < 0.001 - 0.009 < 0.001 < 0.001
CREA (µmol/L) 66
(61 - 75)
77
(72 - 91)
88
(76 - 103)
88
(78 - 102)
66
(60 - 74)
74
(69 - 88)
86
(75 - 100)
87
(75 - 103)
P - < 0.001 < 0.001 < 0.001 - < 0.001 < 0.001 < 0.001
CRP
(mg/L)
3.4
(1.0 - 6.2)
3.4
(0.9 - 6.1)
3.5
(0.9 - 6.0)
3.6
(0.9 - 6.1)
3.3
(0.9 - 6.0)
3.4
(0.9 - 5.9)
3.4
(0.8 - 5.9)
3.5
(0.7 - 5.9)
P - 0.067 0.896 0.409 - 0.615 0.559 0.235
UA
(µmol/L)
280
(230 - 390)
290
(240 - 400)
280
(240 - 400)
270
(230 - 390)
280
(240 - 390)
290
(250 - 410)
290
(240 - 410)
270
(240 - 400)
P - 0.003 0.987 0.007 - 0.005 0.003 0.005
ALP
(U/L)
73
(61 - 85)
74
(59 - 85)
72
(61 - 87)
72
(60 - 90)
69
(58 - 80)
71
(58 - 82)
70
(58 - 82)
70
(58 - 87)
P - 0.030 0.003 0.001 - 0.007 0.003 0.001
SERUM PLASMA
Test
(Unit)
BASAL 1h 2h 4h BASAL 1h 2h 4h
AMY
(U/L)
62
(48 - 73)
65
(49 - 82)
67
(52 - 83)
66
(55 - 81)
61
(44 - 73)
64
(47 - 81)
66
(54 - 82)
65
(52 - 81)
P - < 0.001 < 0.001 < 0.001 - < 0.001 < 0.001 < 0.001
AST
(U/L)
20
(17 - 27)
21
(17 - 27)
21
(17 - 28)
21
(17 - 26)
21
(17 - 27)
21
(17 - 28)
21
(16 - 28)
20
(16 - 25)
P - 0.163 0.601 0.235 - 0.277 0.563 0.087
ALT
(U/L)
23
(17 - 38)
24
(17 - 39)
24
(17 - 39)
24
(18 - 38)
23
(17 - 38)
22
(17 - 38)
22
(18 - 38)
23
(18 - 38)
P - 0.601 0.920 0.888 - 0.587 0.344 0.644
GGT
(U/L)
27
(15 - 41)
27
(15 - 41)
27
(17 - 41)
28
(15 - 42)
27
(15 - 41)
27
(14 - 39)
27
(15 - 39)
27
(15 - 41)
P - 0.736 0.409 0.533 - 0.719 0.684 0.271
LD
(U/L)
176
(149 – 181)
171
(155 – 186)
178
(162 – 223)
172
(163 – 181)
178
(197 – 245)
172
(162 – 233)
180
(162 – 211)
173
(159 – 211)
P - 0.033 0.011 0.043 - 0.028 0.012 0.039
LIP
(U/L)
19
(14 - 27)
26
(20 - 34)
32
(24 - 38)
31
(24 - 39)
19
(15 - 26)
25
(20 - 33)
31
(24 - 40)
31
(23 - 39)
P - < 0.001 < 0.001 < 0.001 - < 0.001 < 0.001 < 0.001
CK
(U/L)
115
(62.9 – 156)
116
(65.9 – 157)
112
(63.5 – 155)
107
(61.8 – 149)
126
(65.9 - 151)
121
(70.0 – 153)
115
(65.3 – 151)
115
(66.5 – 151)
P - 0.324 0.051 0.178 - 0.533 0.615 0.344
TBIL (µmol/L) 10.8
(7.87 - 16.1)
10.3
(8.38 - 14.9)
9.58
(6.33 - 12.8)
7.70
(5.64 - 11.3)
10.9
(8.04 - 15.4)
10.1
(8.55 - 14.5)
9.58
(6.33 - 12.8)
8.21
(5.64 - 11.1)
P - 0.248 0.001 <0.001 - 0.083 0.002 <0.001
DBIL (µmol/L) 4.10
(3.08 - 5.47)
3.76
(3.08 - 4.96)
3.25
(2.39 - 4.28)
2.91
(2.22 - 3.42)
4.62
(3.25 - 5.47)
3.76
(3.08 - 5.13)
3.42
(2.39 - 4.45)
2.91
(2.22 - 3.76)
P - 0.027 < 0.001 < 0.001 - 0.002 < 0.001 < 0.001
Phos (mmol/L) 1.11
(1.07 - 1.17)
1.08
(1.01 - 1.16)
1.19
(1.02 - 1.27)
1.25
(1.13 - 1.36)
0.99
(0.96 - 1.07)
0.95
(0.87 - 1.03)
1.04
(0.90 - 1.12)
1.10
(1.01 - 1.21)
P - 0.018 0.009 0.008 - 0.003 0.004 0.027
Ca
(mmol/L)
2.30
(2.26 - 2.41)
2.37
(2.31 - 2.48)
2.38
(2.33 - 2.49)
2.39
(2.32 - 2.45)
2.30
(2.24 - 2.38)
2.34
(2.28 - 2.45)
2.37
(2.30 - 2.46)
2.38
(2.31 - 2.44)
P - 0.001 < 0.001 < 0.001 - 0.006 0.001 < 0.001
SERUM PLASMA
Test
(Unit)
BASAL 1h 2h 4h BASAL 1h 2h 4h
Mg
(mmol/L)
0.79
(0.75 - 0.83)
0.79
(0.77 - 0.82)
0.83
(0.81 - 0.86)
0.86
(0.82 - 0.87)
0.80
(0.76 - 0.84)
0.79
(0.78 - 0.81)
0.83
(0.81 - 0.85)
0.84
(0.81 - 0.87)
P - 0.587 < 0.001 < 0.001 - 0.338 0.001 < 0.001
Fe
(µmol/L)
17
(13 - 19)
16
(12 - 19)
15
(11 - 18)
11
(9.0 - 15)
17
(12 - 19)
15
(12 - 18)
14
(11 - 18)
11
(9 - 15)
P - 0.794 0.006 0.002 - 0.732 0.004 0.001
Na
(mmol/L)
138
(137 – 139)
139
(138 – 140)
139
(139 – 141)
139
(139 – 140)
138
(137 – 139)
139
(138 – 140)
139
(138 – 141)
139
(138 – 140)
P - 0.764 0.762 0.865 - 0.694 0.703 0.865
K
(mmol/L)
4.08
(3.95 - 4.30)
4.13
(3.98 - 4.23)
4.20
(4.05 - 4.28)
4.18
(4.06 - 4.32)
3.73
(3.55 - 3.90)
3.65
(3.58 - 3.80)
3.69
(3.59 - 3.84)
3.71
(3.54 - 3.85)
P - 0.904 0.586 0.184 - 0.313 0.520 0.384
Cl
(mmol/L)
104
(103 – 105)
104
(103 – 105)
104
(103 – 105)
104
(103 – 105)
104
(103 – 105)
104
(103 – 105)
104
(103 -105)
104
(103 – 105)
P - 0.763 0.965 0.573 - 0.888 0.789 0.942
TSH (mIU/mL) 1.82
(1.03 - 2.21)
1.33
(0.90 - 1.83)
1.41
(0.93 - 1.95)
1.57
(0.94 - 2.12)
1.89
(1.01 - 2.26)
1.40
(0.88 - 1.59)
1.47
(1.02 - 1.97)
1.60
(0.94 - 2.38)
P - < 0.001 0.005 0.031 - <0.001 0.002 0.041
FT4 (pmol/L) 13.6
(12.1 - 15.7)
13.0
(12.4 - 14.7)
12.9
(11.5 - 14.4)
12.7
(11.6 - 14.4)
14.2
(12.0 - 15.0)
13.5
(12.9 - 15.2)
13.3
(12.6 - 15.6)
13.3
(12.4 - 15.4)
P - 0.011 0.009 0.014 - 0.016 0.034 0.036
Ins
(mIU/L)
11.4
(9.19 - 21.2)
75.5
(42.3 – 116)
52.1
(31.8 - 87.8)
30.2
(21.6 - 53.9)
11.7
(9.6 - 19.6)
75.0
(44.6 – 112)
55.0
(33.8 - 91.0)
31.4
(21.7 - 53.2)
P - < 0.001 < 0.001 < 0.001 - < 0.001 < 0.001 < 0.001
Cortisol (nmol/L) 242
(194 – 379)
212
(189 – 285)
195
(125 – 221)
175
(147 – 297)
242
(191 – 382)
206
(190 – 284)
194
(125 – 216)
171
(143 – 293)
P - 0.017 0.010 0.009 - 0.016 0.001 0.013
Results are presented as median (interquartile range). P < 0.05 was considered statistically significant. 1h – 1 hour after breakfast. 2h – 2 hours after breakfast. 3h – 3 hours after breakfast. 4h – 4 hours after breakfast. CHOL – cholesterol. HDL – high density lipoprotein. TG – triglycerides. TP – total protein. Alb – albumin. CREA – creatinine. CRP – C reactive protein. UA – uric acid. ALP – alkaline phosphatase. AMY – amylase. AST – aspartate aminotransferase. ALT – alanine aminotransferase. GGT – gamma glutamyl transferase. LD – lactate dehydrogenase. LIP – lipase. CK – creatine kinase. TBIL – total bilirubin. DBIL – direct bilirubin. Phos – phosphate. Ca – calcium. Mg – magnesium. Fe – iron. Na – sodium. K – potassium. Cl – chloride. TSH – thyroid stimulating hormone. FT4 – free thyroxin. Ins – insulin.
Figure 1

Interferograms. A: TG – triglycerides. B: Ins – insulin. C: cortisol. D: TSH – thyroid stimulating hormone. E: FT4 - free thyroxin. F: TP – total protein. G: Alb – albumin. H: Urea. I: CREA – creatinine. J: LD – lactate dehydrogenase. K: ALP – alkaline phosphatase. L: AMY – amylase. M: LIP – lipase. N: TBIL – total bilirubin. O: DBIL – direct bilirubin. P: Fe – iron. Q: Ca – calcium. R: Phos – phosphate. S: Mg – magnesium. T: UA – uric acid. Hours after the Andean breakfast (x-axis) are plotted against bias values (y-axis). Solid line – bias. Dashed lines - acceptable criteria based on desirable specification for imprecision (DSI) derived from biologic variation.

bm-29-2-020702-f1

Discussion

Our results mirror the metabolic course of TG, Ins and cortisol in the postprandial period (Figure 1A, 1B, and 1C), in accordance with previous findings that evidence the importance of the entero-endocrine system in nutrient sensing and assimilation (17). Moreover, according to Page et al., “following a meal, the gastrointestinal hormones act in concert to regulate appetite, food intake, gastric acid secretion, gastrointestinal motility, and glucose homeostasis” (17). Each of the more than 20 known gastrointestinal hormones were initially thought to be produced by specific enteroendocrine cells, but it is now understood that these cells are flexible and express a range of peptide precursors (18). Moreover, since physicians presently request laboratory thyroid evaluation, avoiding fasting time, a comment is needed: our results (Figure 1D and 1E) showed a significant decrease of both TSH, and FT4 1h after breakfast and no return to baseline in the following 4 hours after food intake. The induced elevation of circulating somatostatin in the postprandial period and the consequent suppression of TSH could explain these results (19). This is in accordance with independent researchers that showed similar results by using different analytical methods for TSH and FT4 assays (19, 20). Therefore, patients should be in a fasting condition to avoid both unclear thyroid laboratory results, and a misdiagnosis of hypothyroidism.

The Andean breakfast statistically modified both TP and Alb concentrations (Figure 1F and 1G). These results are in agreement with other studies, which showed that feeding stimulates Alb and other protein syntheses, since this event might improve the storage of essential amino acids (21-24). Moreover, Lima-Oliveira et al., have shown a similar result for Alb after a light Italian meal, without significant changes in total protein (13). However, the Andean breakfast is richer in proteins than the light Italian meal – 24.9 g vs. 14.6 g – and this could explain the differences that were shown. Furthermore, the higher protein content of the Andean breakfast can also explain the urea and CREA results (Figure 1H and 1I). Thus, the outcome of such laboratory tests on non-fasting patients can interfere with the validity of the results and possibly, jeopardize patient safety.

Regarding enzymes, either transaminases (AST, ALT), gamma-glutamyl transferase or creatine kinase, did not show statistically relevant changes after the Andean breakfast (Table 3); LD and ALP showed statistical relevant changes after the Andean breakfast with variability in conformity with DSI (Table 3, Figure 1J and 1K). However, a significant increase in AMY and LIP activities was shown (Figure 1L and 1M). Boivin et al., had experimentally demonstrated that the activity of pancreatic enzymes are influenced by diet type (25). This can explain why our results differ from Lima-Oliveira et al., who did not evidence changes for either AMY or LIP in the Italian study with a light meal (13).

The significant decrease observed for bilirubin (Figure 1N and 1O) is in agreement with Meyer et al. (26). Iron fluctuations caused by intra-day variability and by the diet are thought to influence test results, and may affect clinical patient management (27). Moreover, the measurement of electrolytes is frequently requested and tested on patients avoiding fasting time. Our results showed a significant decrease of Fe concentration at 2h and 4h following the Andean breakfast (Figure 1P), whereas Ca, Phos and Mg significantly increased after food intake (Figure 1Q, 1R and 1S). Therefore, fasting should be required for evaluating bilirubin, iron, calcium, phosphate, and magnesium.

Differences demonstrated between serum and plasma are in agreement with the recent critical review published by Lima-Oliveira et al.: i) the concentration of proteins was higher in serum than in plasma; ii) differences between serum and plasma were observed for some enzymes tested; and iii) Ca, Phos and Mg were higher in serum than in plasma, since heparin can bind these ions (Figure 1) (28).

In conclusion, an Andean breakfast can affect routine biochemistry and immunochemistry laboratory tests and might jeopardize patient safety. Therefore, COLABIOCLI WG-PRE-LATAM calls attention and highlights that the fasting time needs to be carefully considered when performing tests, in order to prevent spurious results and reduce laboratory errors. Laboratory quality managers are encouraged to standardize the fasting requirements in their laboratory (i.e., 12h) using the evidence reported above.

Acknowledgments

Our grateful thanks for the Interlab directors’: Jorge Macías Loor and Vicenta Cevallos Carofilis for accepting to be partners in this study; with special thanks to the laboratory professionals Miguel Mendoza, Karla Yaguana and Jhonny Pihuave for performing the analytical tests and assays. Our sincere thanks to Maria Auxiliadora
Alarcon Perasso, doyenne from the Faculty of Chemistry at the University of Guayaquil, Ecuador for the recruitment of all volunteers. Our gratitude to Riccardo Fiore F.L. Medical (Torreglia, Italy) that partially supported the project ADR 2451/15.

Notes

[1] Conflicts of interest None declared.

References

1 

Sánchez-Llaguno SN, Neira-Mosquera JA, Pérez-Rodríguez F, Moreno-Rojas R. Preliminary nutritional assessment of the Ecuadorian diet based on a 24h food recall survey in Ecuador. Nutr Hosp. 2013;28:1646–56.

2 

Mateos-Marcos S, Villena-Esponera MP, Moreno-Rojas R. Nutritional assessment of Esmeraldan adult population (Ecuador). Rev Nutr. 2017;30:735–46. https://doi.org/10.1590/1678-98652017000600006

3 

Lima-Oliveira G, Volanski W, Lippi G, Picheth G, Guidi GC. Pre-analytical phase management: a review of the procedures from patient preparation to laboratory analysis. Scand J Clin Lab Invest. 2017;77:153–63. https://doi.org/10.1080/00365513.2017.1295317

4 

Lima-Oliveira G, Lippi G, Salvagno GL, Picheth G, Guidi GC. Laboratory Diagnostics and Quality of Blood Collection. J Med Biochem. 2015;34:288–94. https://doi.org/10.2478/jomb-2014-0043

5 

Simundic AM, Cornes M, Grankvist K, Lippi G, Nybo M. Standardization of collection requirements for fasting samples: for the Working Group on Preanalytical Phase (WG-PA) of the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM). Clin Chim Acta. 2014;432:33–7. https://doi.org/10.1016/j.cca.2013.11.008

6 

Nordestgaard BG, Langsted A, Mora S, Kolovou G, Baum H, Bruckert E, et al. Fasting Is Not Routinely Required for Determination of a Lipid Profile: Clinical and Laboratory Implications Including Flagging at Desirable Concentration Cutpoints-A Joint Consensus Statement from the European Atherosclerosis Society and European Federation of Clinical Chemistry and Laboratory Medicine. Clin Chem. 2016;62:930–46. https://doi.org/10.1373/clinchem.2016.258897

7 

Simundic AM, Bolenius K, Cadamuro J, Church S, Cornes MP, van Dongen-Lases EC, et al. Joint EFLM-COLABIOCLI Recommendation for venous blood sampling. Clin Chem Lab Med. 2018;56:2015–38. https://doi.org/10.1515/cclm-2018-0602

8 

Guidi GC, Simundic AM, Salvagno GL, Aquino JL, Lima-Oliveira G. To avoid fasting time, more risk than benefits. Clin Chem Lab Med. 2015;53:e261–4. https://doi.org/10.1515/cclm-2014-1013

9 

Lima-Oliveira G, Valentim CD, Guidi GC. Lipid profile, changes in laboratory prescriptions are necessary. J Clin Lipidol. 2017;11:768–9. https://doi.org/10.1016/j.jacl.2017.03.002

10 

Lippi G, Salvagno GL, Lima-Oliveira G, Brocco G, Danese E, Guidi GC. Postural change during venous blood collection is a major source of bias in clinical chemistry testing. Clin Chim Acta. 2015;440:164–8. https://doi.org/10.1016/j.cca.2014.11.024

11 

Lima-Oliveira G, Lippi G, Salvagno GL, Montagnana M, Manguera CL, Sumita NM, et al. New ways to deal with known preanalytical issues: use of transilluminator instead of tourniquet for easing vein access and eliminating stasis on clinical biochemistry. Biochem Med (Zagreb). 2011;21:152–9. https://doi.org/10.11613/BM.2011.024

12 

Lima-Oliveira G, Guidi GC, Salvagno GL, Brocco G, Danese E, Lippi G. Estimation of the imprecision on clinical chemistry testing due to fist clenching and maintenance during venipuncture. Clin Biochem. 2016;49:1364–7. https://doi.org/10.1016/j.clinbiochem.2016.07.007

13 

Lima-Oliveira G, Salvagno GL, Lippi G, Gelati M, Montagnana M, Danese E, et al. Influence of a regular, standardized meal on clinical chemistry analytes. Ann Lab Med. 2012;32:250–6. https://doi.org/10.3343/alm.2012.32.4.250

14 

Lima-Oliveira G, Lippi G, Salvagno G, Brocco G, Guidi GC. In vitro diagnostic company recalls and medical laboratory practices: an Italian case. Biochem Med (Zagreb). 2015;25:273–8. https://doi.org/10.11613/BM.2015.028

15 

Simundic AM. Practical recommendations for statistical analysis and data presentation in Biochemia Med journal. Biochem Med (Zagreb). 2012;22:15–23. https://doi.org/10.11613/BM.2012.003

16 

Westgard J. Desirable Biological Variation Database Specifications. Available at: http://www.westgard.com/biodatabase1.htm2014. Accessed October 16th 2018.

17 

Page LC, Gastaldelli A, Gray SM, D’Alessio DA, Tong J. Interaction of GLP-1 and Ghrelin on Glucose Tolerance in Healthy Humans. Diabetes. 2018;67:1976–85. https://doi.org/10.2337/db18-0451

18 

Psichas A, Reimann F, Gribble FM. Gut chemosensing mechanisms. J Clin Invest. 2015;125:908–17. https://doi.org/10.1172/JCI76309

19 

Kamat V, Hecht WL, Rubin RT. Influence of meal composition on the postprandial response of the pituitary-thyroid axis. Eur J Endocrinol. 1995;133:75–9. https://doi.org/10.1530/eje.0.1330075

20 

Scobbo RR, VonDohlen TW, Hassan M, Islam S. Serum TSH variability in normal individuals: the influence of time of sample collection. W V Med J. 2004;100:138–42.

21 

Jefferson LS. Lilly Lecture 1979: role of insulin in the regulation of protein synthesis. Diabetes. 1980;29:487–96. https://doi.org/10.2337/diab.29.6.487

22 

De Feo P, Horber FF, Haymond MW. Meal stimulation of albumin synthesis: a significant contributor to whole body protein synthesis in humans. Am J Physiol. 1992;263:E794–9.

23 

Hunter KA, Ballmer PE, Anderson SE, Broom J, Garlick PJ, McNurlan MA. Acute stimulation of albumin synthesis rate with oral meal feeding in healthy subjects measured with [ring-2H5]phenylalanine. Clin Sci (Lond). 1995;88:235–42. https://doi.org/10.1042/cs0880235

24 

Caso G, Feiner J, Mileva I, Bryan LJ, Kelly P, Autio K, et al. Response of albumin synthesis to oral nutrients in young and elderly subjects. Am J Clin Nutr. 2007;85:446–51. https://doi.org/10.1093/ajcn/85.2.446

25 

Boivin M, Lanspa SJ, Zinsmeister AR, Go VL, DiMagno EP. Are diets associated with different rates of human interdigestive and postprandial pancreatic enzyme secretion? Gastroenterology. 1990;99:1763–71. https://doi.org/10.1016/0016-5085(90)90485-J

26 

Meyer BH, Scholtz HE, Schall R, Müller FO, Hundt HK, Maree JS. The effect of fasting on total serum bilirubin concentrations. Br J Clin Pharmacol. 1995;39:169–71. https://doi.org/10.1111/j.1365-2125.1995.tb04424.x

27 

Nguyen LT, Buse JD, Baskin L, Sadrzadeh SMH, Naugler C. Influence of diurnal variation and fasting on serum iron concentrations in a community-based population. Clin Biochem. 2017;50:1237–42. https://doi.org/10.1016/j.clinbiochem.2017.09.018

28 

Lima-Oliveira G, Monneret D, Guerber F, Guidi GC. Sample management for clinical biochemistry assays: Are serum and plasma interchangeable specimens? Crit Rev Clin Lab Sci. 2018;55:480–500. https://doi.org/10.1080/10408363.2018.1499708