Type of test Urine; blood; various

Normal findings

 Negative

Test explanation and related physiology

Substance abuse testing is used mostly by employers and law enforcement agencies. Industrial testing is used at the time of preemployment, prepromotion, annual physical examination, after an accident when there is reasonable suspicion, or for random testing or follow-up treatment surveillance.

Most commonly, a drug screen is performed to detect small amounts of any number of metabolites of commonly used drugs. If the screen result is positive, a more accurate and quantitative test is performed on the same specimen. Drug screens are available for a variety of drug categories. The most common are amphetamines, barbiturates, benzodiazepines, cannabinoids (marijuana [THC]), cocaine, methamphetamine, opiates (morphine and heroin), phencyclidine (PCP), carisoprodol, meprobamate, and propoxyphene (Table 1). Alcohol testing is most commonly used by law enforcement. Not only is drug testing helpful in identifying users, it also acts as a deterrent. Athletes can be tested for anabolic hormones, stimulants, diuretics, beta-blockers, street drugs, antiestrogens, erythropoietin, and beta-2 agonists that may unfairly improve their performance. Health and life insurance companies routinely test for illicit drugs.

Table1. Typical multipanel drug screen

Until recently, substance abuse testing has used urine exclusively as the sample of choice. Urine drug testing is generally inexpensive. Urine is easily obtained, and it contains a large amount of drug metabolites. More important, whereas urine can identify drug usage for several days after the last usage, blood testing reflects drug usage only during the past few hours.

Saliva, breath, hair, and sweat are becoming increasingly important and accurate specimens for specific drug testing. These testing methods are very expensive, however. Hair samples detect the presence of drugs used during the past 3 months. In addition, hair and nail samples may be used to detect or document exposure to arsenic and mercury.

Because a positive result can have a profound effect on a per son’s life, job, and accountability, it is common for a drug abuser to attempt to alter the urine specimen. Specimen validity is very important. Ideally, all urine specimens should be observed. Unannounced testing is another way to improve validity. Therefore the urine sample is tested for odor, color, temperature, creatinine, pH, and specific gravity to ensure that it is a proper specimen. Results can be affected by genetic disorders in drug metabolism (e.g., CYP2D6 or catechol-O- methyltransferase) and drug receptor variations (e,g., opiod receptor exon 1). This must be considered in result interpretation.

Toxicology screening tests for drug overdose and poisoning (e.g., lead and carbon monoxide) are best performed on blood. Results indicate current drug levels, which are used to determine or alter therapy. Toxicology studies are used to incriminate drugs as a cause or factor in the death of a person.

 Interfering factors

• Poppy seeds can cause positive opiate results.

• Secondhand marijuana smoke can cause positive THC results.

• Detergents, bicarbonates, salt tablets, and blood can all foil accurate drug testing in a urine specimen.

* Ibuprofen can cause a false-positive THC result in some assays.

* Cold remedies can cause false-positive amphetamine results in some assay systems.

* Antibiotics (e.g., amoxicillin) can cause false-positive results for heroin and/or cocaine.

* Aggressive use of diuretics can decrease urine drug levels.

Procedure and patient care

 Before

* Explain the procedure to the patient or significant others.

 • If the specimen is obtained for medicolegal testing, ensure that the patient or family member has signed a consent form.

 • Obtain a list of prescription medicines that the patient is taking that may alter or confuse screening results. Obtain as much information as possible about the drug type, amount, and ingestion time.

 • Carefully assess the patient for respiratory distress.

During

 • Collect blood and urine samples as designated by the laboratory.

 • Ensure that patients provide their own urine. Urine specimens for substance abuse testing are usually collected in the presence of a healthcare provider.

 • Be sure that the patient does not alter the urine specimen.

 • For hair testing, cut 50 strands of hair from the scalp.

• A second confirmatory specimen may be obtained (and is used if results are positive).

 • Collect gastric contents as indicated by the specific institution. A nasogastric tube is required.

After

 • Apply pressure to the venipuncture site.

• Refer the patient for appropriate drug and psychiatric counseling.

• Follow the chain of custody for the specimen as provided by standard guidelines of the institution.

• Place the specimen in the required container for delivery.

 • Check the temperature of urine specimens within 3 minutes after voiding. The temperature should be between 97° and 99° F.

 • The specimen may be sent to a nationally certified laboratory for federal workers or workplace testing. Local hospital laboratories are often able to test for many drugs.

 Abnormal findings

- Positive drug level

اخر الاخبار

اخبار العتبة العباسية المقدسة

معهد القرآن الكريم النسويّ يعقد الجلسة الرابعة من مسابقة فضة القرآنية

العتبة العباسية المقدسة تهيّئ الصحن الشريف استعدادًا لمهرجان رحمة للعالمين الدولي الأوّل

بمشاركة عددٍ من الطلبة.. المجمع العلمي ينظّم دورة مختصّة بالتجويد في محافظة الديوانية

العتبة العباسية المقدسة تنشر لافتات احتفائية بذكرى المولد النبوي الشريف

المزيد

الآخبار الصحية

هل من الآمن شرب القهوة على معدة فارغة؟

تحذير: مرض السكري يسرق طاقة قلبك

حقيقة صادمة.. لماذا يجب أن تتوقف عن شراء الجزر الصغير؟

بعد عمر الستين.. توقيت وجبة الإفطار مؤشر على صحتك

المزيد

الآخبار التكنلوجية

تركيب مقعد الطفل بأمان في سيارتك: دليل كامل وسهل

مليار مليار عملية في الثانية.. ألمانيا تدشن الحاسوب الفائق

أخيرا.. إنستغرام يصل رسميا إلى آيباد

حل يثير جدلا طبيا.. حقنة قادرة على إخفاء الشيب من رأسك ؟!

المزيد

مواضيع ذات صلة

syphilis detection test (Serologic test for syphilis [STS], Venereal Disease Research Laboratory [VDRL], Rapid plasma reagin [RPR], Fluorescent treponemal antibody test [FTA])

sweat test (Sweat electrolyte test, Sweat chloride test, Sweat conductivity test, Iontophoretic sweat test)

Streptococcus serologic testing (Antistreptolysin O titer [ASO], Antideoxyribonuclease-B titer, [Anti-DNase-B, ADNase-B, ADB], Streptococcus group B antigen detection, Streptozyme)

Galectin-3

Biomarkers of Collagen Synthesis and Degradation

Cardiac Fibrosis

stool for leukocytes (White blood cell stool test, Fecal leukocyte stain, Stool for white cells)

stool culture (Stool for culture and sensitivity [C&S], Stool for ova and parasites [O&P])

stool cancer screening (stool for occult blood, Stool for OB, Fecal occult blood test [FOBT], Fecal immunotest [FIT], DNA stool sample)

Biomarkers of Myocardial Remodeling and Fibrosis

Pathophysiological and Clinical Interpretations of Changes in circulating BNP/NTproBNP

sputum cytology