Aminolevulinic Acid (ALA, Delta-Aminolevulinic Acid, Delta-ALA)



Test Description

Aminolevulinic acid (ALA), a urine pigment, is the precursor to porphobilinogen
(PBG) in the formation of heme of hemoglobin. Subsequent steps include: PBG
leading to formation of uroporphyrinogen III/uroporphyrin III, followed by formation
of coproporphyrinogen III/coproporphyrin III, then protoporphyrinogen/                    
protoporphyrin. This process then leads to heme formation. If a problem occurs during
heme formation, the ALA accumulates and is excreted in the urine. ALA is normally
absent from urine.                                                                                                          
The presence of ALA in the urine usually indicates lead poisoning. The test can        
be used as a screening device for detection of excessive absorption of lead before     
the appearance of symptoms.                                                                                        
Concentrations of ALA are greatly increased in many patients with acute neurological
forms of porphyrias. ALA testing may be ordered in patients with symptoms             
suggestive of acute porphyria, such as abdominal pain, nausea, constipation,              
peripheral neuropathy, muscle weakness, urinary retention, confusion, and                 
hallucinations.

Normal Values

Random specimen:                0.1–0.6 mg/dL (7.6–45.8 μmol/L SI units)                             
24-hour urine:                       1.5–7.5 mg/dL/24 hour (11.15–57.2 μmol/24 hours SI units)

Possible Meanings of Abnormal Values

Increased                                                                                                                                  
Acute porphyria
Chronic alcohol abuse
Hepatitis
Hepatic carcinoma
Lead exposure
Lead poisoning

Contributing Factors to Abnormal Values

• Failure to protect the urine from light may alter test results.
• Drugs which may increase ALA levels: barbiturates, griseofulvin, penicillin,
   rifampin.

        Interventions/Implications
Pretest 

• Explain 24-hour urine collection procedure to the patient.
• Stress the importance of saving all urine in the 24-hour period. Instruct the patient to
   avoid contaminating the urine with toilet paper or feces.
• Inform the patient that there is no preservative in the collection bottle. It must be refrigerated
  during and after collection. The container should be wrapped in aluminum foil to
   protect the specimen from light. 

Procedure

• Obtain the proper container from the laboratory.
• Begin the testing period in the morning after the patient’s first voiding, which is
discarded.
• Timing of the 24-hour period begins at the time the first voiding is discarded.
• All urine for the next 24 hours is collected in the container, which is to be kept
  refrigerated.
• If any urine is accidentally discarded during the 24-hour period, the test must be discontinued
  and a new test begun.
• The ending time of the 24-hour collection period should be posted in the patient’s room.
• Gloves are worn whenever dealing with the specimen collection.
Posttest
• At the end of the 24-hour collection period, label and send the urine container on ice to
  the laboratory as soon as possible.
• Report abnormal findings to the primary care provider

تعليقات

إرسال تعليق

المشاركات الشائعة من هذه المدونة

Anti-Parietal Cell Antibody

Test Description The anti-parietal cell antibody test (APCA) measures the presence of antibodies against gastric parietal cells. When antibodies form against the parietal cells in the stomach, their production of intrinsic factor is disrupted. This results in pernicious anemia due to an autoimmune process. Thus the APCA test is used in the evaluation of pernicious anemia. It may be elevated in atrophic gastritis and in some other autoimmune processes. Normal Values Negative Possible Meanings of Abnormal Values Positive CREST syndrome Scleroderma Contributing Factors to Abnormal Values • Drugs that may increase antiscleroderma antibody levels: aminosalicylic acid, isoniazid,   methyldopa, penicillin, propylthiouracil, streptomycin, tetracycline.    Interventions/Implications Pretest • Explain to the patient the purpose of the test and the need for a blood sample to be drawn. • No fasting is required before the test. Procedure • A 7-mL bl...
قراءة المزيد

انواع تحاليل السكر

1- تحليل السكر العشوائي  R.B.S { Random Blood Glucose }  فائدته فقط أنه يعطي فكرة عامة عن مستوى السكر في دم المريض حيث يتم تحليل العينة في أي وقت خلال اليوم ، سواء لمريض السكر أو الشخص السليم وتؤخذ نتائج هذا التحليل إلى الطيبب ليقوم بتقييم حالة المريض. 2- تحليل سكر الصائم: F.B.S { Fasting Blood Glucose }   يجرى هذا التحليل على المريض بحيث يكون صائمآ من 6 – 8 ساعة علمآ أن المستوى الطبيعي للسكر في الدم يتراوح ما بين 70 – 110 مجم لكل 100ملليتر دم، فإذا زادت النسبة عن 120 فهذا مؤشر لحدوث الاصابة بالسكر في المستقبل، وإذا تجاوزت 130 فهذا يعتبر مريضآ بالسكر، ويتم التأكد من ذلك بإعادة التحليل لمرتين أو 3 مرات متتابعة على الأقل بفاصل اسبوع بين كل قياس.  3- تحليل السكر بعد ساعتين من الأكل  P.P.S { Post Prandial Sugar } يتم هذا التحليل على المريض بعد وجبة طبيعية ( أو 75 جرام جلوكوز) ثم نقيس له السكر في الدم بعد ساعتين من الاكل ، وفائدة هذا التحليل أنه يعطينا فكرة عن مستقبل حدوث مرض السكر عند هذا المريض وهل سوف يحتاج إلى تحليل منحنى السكر أو لا. فإذا تجاوز...
قراءة المزيد