This study compares two methods for detecting amphetamines in urine samples: immunochromatography (IC) strip and enzyme immunoassay (EIA) using Vitros 5.1 FS. Out of 210 urine samples, the IC strip showed a 28.6% false positive rate compared to EIA, which is recommended for confirmation due to its higher specificity. The findings highlight the need for more reliable detection methods in areas with rising drug abuse rates.

1. Thecomparison methods of amphetamines detection in urine samples in
Thammasat University hospital, Pathumtani province.
Kridsada Sirisabhabhorn Supaporn Pumpa Narumon Sereekhajornjaru and Palakorn Puttarak
Department of Medical Technology Laboratory, Thammasat University Hospital Pathumtani, Thailand
Introduction
Amphetamines (AMPH) has stimulated to nervous system in the body. The addicts’ behavior of AMPH had related with many illegitimacy and criminal problems
especially in Pathumtani province where risk of drugs spreading. The method of competitive direct immunochromatography (IC) strip, has been used for a long period but
reliability of result is not still observe in present. However positive result in IC strip need to confirm with other technique which higher sensitivity & specificity than IC
principle. Also homogeneous enzyme immuno assay (EIA) was available in our laboratory. This point interesting in compared results of 2 methods, IC strip & EIA that
measured AMPH in urine sample.
Abstract
Proposed for compare results available from 2 methods, IC strip and EIA by VITROS 5,1 FS which AMPH diagnosis in routine
using.
Objective :
Materials & Methods
All previous data were obtained from 210 cases including patients and cadavers obtained from branch of Forensic Sciences Institute, Thammasat University
hospital. Firstly all sample were perform AMPH screening by IC strip then positive result was confirmed by EIA with VITROS 5,1 FS (cut off >1,000 ng/ml; positive)
Descriptive statistic was used for data analysis.
Results
Conclusion
References
Karch S. Drug Abuse Handbook 1st. Ed. New York: CRC Press; 1997, 174-177.
Goodwin JS, Larson GA, Swant J, Sen N, Javitch JA, Zahniser NR. et al. Amphetamine and Methamphetamine differentially affect dopamine transporters in vitro and in vivo. The Journal of
Biological Chemistry. 2009; 284 . 2978-89.
Oyler JM, Cone EJ, Joseph RE, Moolchan ET., and Huestis1 MA. Duration of detectable Methamphetamine and Amphetamine excretion in urine after controlled oral administration of
Methamphetamine to humans. Clinical Chemistry 2002; 48:10 1703–14.
Nowadays, the incidence of drug abuse in Pathumtani province is continuously rising and also influences the increasing of patient treatment in each year.
Amphetamines, a common name AMPH is drug relevant to nervous system stimulation. Amphetamines are eliminated via multiple pathways including diverse routes
of hepatic transformation and by renal elimination. Therefore, the noninvasive method to quantify the level of amphetamines in urine sample as well as the rapid test
and cheap is ideal. The immunochoromatography (IC) strip is used for the routine analysis once the positive was shown, enzyme immunoassay (EIA) is required for
confirmation. The propose of this study was to compare 2 methods, IC & EIA. Retrospective clinical data was performed from 210 samples patients and cadavers
obtained from branch of Forensic Sciences Institute, Thammasat University hospital. AMPH screening method was performed with AMPH strips, IC, and confirmed with
VITROS 5,1 FS, EIA (cut off 1,000 ng/ml). The descriptive statistics was used for analysis. The study demonstrated that AMPH strip were compatible with VITROS 5,1
FS, values as 71.4 % (N=150) and shown false positive as 28.6 % (N=60). The age of samples were positive for AMPH in urine described mean value as 27.9 years (25.9-
29.8) and median values of AMPH in positive sample illustrated as 7,926.5 and 2,561 ng/ml in patients and cadavers groups respectively. Conclusion, this study was
shown high percentage of false positive when perform with IC strip. Confirmation which high specificity assay method is recommend. Although mass spectrometry (MS)
is a reference method which require exclusive experience, long turn around time and high cost but confirmation method is still significant before result approve.
Additionally the prevalence of AMPH or drug abuse need to investigate in this province further that may be response authority to inhibit drugs spread. The profit of this
study emphasize to develop AMPH measurement approach for reliable detection.
Key words : Amphetamines, immnunochromatography, enzyme immuno assay, method
This study was demonstrated that IC method shown high false positive results (28.6%) when compared with EIA by VITOS 5,1. FS, reference technique available
in generally laboratory. Average of age who hold in AMPH positive in urine is 27.9 years within 25.9-29.8 years, 95% CI. Finally median values of AMPH in urine of
patients group is higher more than cadavers group which illustrated on figure 1 above.
Although mass spectrometry (MS) is reference method for measure AMPH but that required expert technician, turn around time result and spend high cost.
Particularly, this area is risk of drug abuse spread so screening of AMPH with higher technique than IC strip is still need to develop and perform further in endemic area
because of that relevant to many criminal cases. However EIA technique is still suitable for AMPH screening for benefit to monitoring patient and reliable in initially
diagnosis. Finally the comparison method between EIA with MS suggest to study in the future.
Age of AMPH positive in urine samples
Variable | Obs Mean Std. Err. [95% Conf. Interval]
-------------+---------------------------------------------------------------
age | 95 27.86316 .9769586 25.92338 29.80293
Acknowledgement : We would like thank to Waruneeh Hanpitakpong, Ph.D. for advisor.
Comparison results available of
IC strip and EIA; ref.
Negative Positive
Gender % N % N
Female 6.2 13 10.5 22
Male 22.4 47 55.7 117
Unidentified 0 0 5.2 11
Total 28.6 60 71.4 150
6793
6448
9618
6105
24945
8686
206950
1685
44942
10373
56248
1000
4405
6147
1292
1360
1259
5332
23040
5162
57610
11055
1995
2176
34435
12509
12298
16422
33954
12517
1557
7167
19858.90625
2479
2561
68233
5208
2100
1212
9372
13023.57
0
50000
100000
150000
200000
250000
0 5 10 15 20 25 30 35
ValuesofAMPH(ng/ml)
Number ofurine samples
Fig. 1 Comparisonof median values of AMPH in urine samples in patient and
cadavergroupswere analyzedby VITROS 5,1 FS.
Patients
Cadavers
Negative
Positive
Immunochromatography strip Homogeneous enzyme immuno assay, VITROS 5,1 FS,
Johnson & Johnson company
Positive result : >1,000 ng/ml
Table 1. Illustrated compatible results in EIA with VITROS 5,1 FS after results in
positive by immunochromatography strip.
Table 2. Illustrated mean of age in AMPH positive cases in this study.
We declare no conflict interest in this
study.