Category Archives: Mohammed Shedeed‏

cbc manual

تقدير الهيموجلوبين بطريقة الدرابكن : Drabkin Method

 

 

تقدر كمية الهيموجلوبين بقياس اللون الناتج عن اتحاده بالسيانيد بجهاز قياس الطيف الضوئي (Spectrophotometer )

 

ويجب ان يكون لون محلول التخفيف اصفر باهتا رائقا يعطي درجة امتصاص صفر عند قراءته علي جهاز القياس الطيفي عند طول موجي 540 نانوميتر باستعمال الماء المقطر (Blank)

تنتج الشركات كاشف لتقدير الهيموجلوبين بطريقة السيانيد يتم تخفيفه باتباع إرشادات الشركة المنتجة.

يحفظ محلول التخفيف في زجاجة بنية اللون لعدة شهور في درجة حرارة الغرفة.

كيفية العمل :

1. يوضع 5 مل محلول درا بكين + 20 ميكروليتر (20ul) دم باستخدام ماصة أوتوماتيكية ( أو ماصة الهيموجلوبين ) .

2. ترج الأنبوبة تم تترك لمدة 3 – 5 دقائق حتي يتم التفاعل .

3. يقرا علي طول موجي 540 نانوميتر بعد ضبط صفر الجهاز باستخدام محلول درابكين .

4. تقرأ عينة قياسية (Standard) علي الجهاز الحساب : درجة امتصاص الاختبار X تركيز المحلول القياسي X معامل التخفيف ———————- —————————————— درجة امتصاص القياسي 100 = تركيز الهيموجلوبين _ بالجرام / 100 مليلتر ) .

ملحوظة :

هناك بعض الكواشف يمكن قراءة نسبة الهيموجلوبين من جدول مرفق بالكاشف أو بعملية حسابية بسيطة وذلك في حالة عدم وجود المحلول القياسي.

 

 

طريقة أعداد منحني قياسي وجدول قياسي :

 

تعمل تخفيفات متتالية من المحلول القياسي Standard المعروف درجة تركيزه كآلاتي : 2:1 و 3:1 و 4:1 و 5:1وتقرا هذه التخفيفات بعد ضبط صفر الجهاز بمحلول درابكين.

يرسم منحني بياني تقدير الهيموجلوبين بالجرام / لتر في كل قراءة ومنه يمكن عمل جدول قياسي لكافة القراءات وينصح بقياس المحلول القياسي عند تغيير الكاشف أو اجراء صيانة للجهاز.

 

 

المعدل المرجعي :

 

 

الفئة النسبة بالجرام

الرجال

13 –18 جم %

السيدات

11.5 – 16.5 جم %

أطفال (حديث الولادة)

16.5 – 19.5 جم %

أطفال (ثلاثة شهور)

9.5 – 13.5 جم %

أطفال السنة الأولى

1.05 – 13.5 جم %

أطفال السنة الأولى

1.05 – 13.5 جم %

أطفال 3 – 6 سنوات

12 –14 جم %

أطفال 10 – 12 سنة

11.5 – 14.5 جم %

سيدات حوامل

لا يقل عن 11 جم %

 

 

 

http://www.drguide.mohp.gov.eg/newsi…s/image012.jpg

2- العد الكلي لكرات الدم الحمراء R.B.Cs Counting

 

 

العد بواسطة المجهر وشريحة العد Haemocytometer كيفية العمل :

1. يخفف الدم 200:1 في محلول التخفيف وذلك بإضافة 20 ميكروليتير دم إلى 4 مل محلول في أنبوبة وازمـــان ( يمكن اخذ العينة بواسطة الماصـــة ذات الانتفاخ والمقسمة 0.5 – 1 – 101 وذلك بسحب الدم حتى 0.5 ثم التكملة حتى 101 بمحلول التخفيف).

 

 

http://www.drguide.mohp.gov.eg/newsi…s/image013.jpg

 

2. ترج الأنبوبة جيدا لمدة دقيقتين علي الأقل ( أو الماصة ).

 

3 . تملا شريحة العد بماصة شعرية أو ماصة باستير بعد وضع غطاء الشريحة.

4. تعد كريات الدم الحمراء بواسطة العدسة الشيئية X 10 أو X40 علي أن يدخل في العد الكريات التي تمس القاع والحدود الشمالية للمربعات الصغيرة في 5 مربعات من المربع الأوسط للشريحة ( المربعات الأربعة علي الأطراف + المربع الأوسط ).

 

 

طريقة العد :

 

خمس مربعات من المربع الأوسط في شريحة العد .

الحساب :

عدد كريات الدم الحمراء /مم3 = عدد الكريات * 10000

 

 

أسباب الزيادة في عدد كريات الدم الحمراء :

 

نقص الأكسجين – أمراض القلب وامراض تليف الرئتين ووجود بعض أنواع الهيموجلوبين غير الطبيعي.

 

 

أ- أخطاء تؤدي إلى زيادة العدد

 

1. حجم الدم اكثر من 20 ميكروليتر أو حجم المحلول اقل من الحجم المطلوب.

2. عدم مزج العينة جيدا مع محلول التخفيف.

3. توزيع كريات الدم الحمراء في شريحة العد غير متوازن.

4. مل خاطئ لشريحة العد.

5. عد جميع كريات الدم الحمراء الملامسة للخطوط الجانبية.

 

 

أسباب نقص كريات الدم الحمراء :

 

 

  • أمراض الدم مثل اللوكيميا وفشل النخاع العظمي …. الخ

ب- أخطاء تؤدي إلى نقص العدد:

 

 

1. حجم الدم اقل من 20 ميكروليتر أو حجم المحلول اكثر من الحجم المطلوب.

2. إرجاء العد لمدة طويلة.

3. وجود جلطة صغيرة في العينة.

4. وجود فراغات هوائية أو شوائب.

5. استعمال شريحة غير نظيفة.

 

 

المعدل المرجعي :

 

 

الفئة النسبة – ملليمتر المكعب

الرجال

4.5 –6.5 مليون / ملليمتر المكعب

النساء

3.8 – 5.8مليون / ملليمتر المكعب

أطفال (3 شهور)

3.2 – 4.8 مليون / ملليمتر المكعب

أطفال( 3 – 6 أعوام)

4.1 – 5.5 مليون / ملليمتر المكعب

أطفال (10 – 12 عام)

4 – 5.4 مليون / ملليمتر المكعب

 

 

3- العد الكلي لكريات الدم البيضاء : Total Leucocytic Counting

 

بواسطة المجهر وشريحة العد Haemocytometer

محلول التخفيف يحلل كريات الدم الحمراء ويصبغ انويه كريات الدم البيضاء بلون بنفسجي فيسهل عدها.

كيفية العمل :

1- يخفف الدم 2:1 باستخدام الماصة ذات الانتفاخ المدرجة 0.5 ، 1 ، 11 بملئها بالدم حتى علامة 0.5 ثم بالمحلول حتى علامة 11.

2- يمكن عمل نفس التخفيف 20 ميكروليتر إلى 0.38 مل من المحلول ( باستعمال الماصة الأوتوماتيكية ) في أنبوبة زجاجية.

 

 

http://www.drguide.mohp.gov.eg/newsi…s/image014.jpg

 

3- ترج الأنبوبة جيدا.

 

4- تملا شريحة العد بواسطة ماصة باستير بعد وضع غطاء زجاجي للشريحة.

5- تعد كريات الدم البيضاء في المربعات الأربعة الخارجــــية باستخدام العدسة الشيئية ( *10) للمجهر.

الحساب :

عدد كريات الدم البيضاء /مم3 :

عدد الكريات * 100/2 = عدد الكريات * 50

 

 

http://www.drguide.mohp.gov.eg/newsi…s/image015.jpg

 

 

الأخطاء التي تؤدي إلى زيادة أو نقص عدد كريات الدم البيضاء :

 

 

  • نفس الأسباب التي تم ذكرها عند عد كريات الدم الحمراء . لتلافي هذه الأخطاء يمكن عد عينه أخري أو عدد أكبر من الكريات البيضاء.

أسباب الزيادة في عدد كريات الدم البيضاء:

 

 

1. زيادة فسيولوجية أثناء الحمل والولادة ، عقب مجهود عضلي وفي الأطفــال حديثي الولادة (18000 – 25000/مم3).

2. زيادة مرضية – العدوي بالميكروبات العنقودية والسبحية مثل التهاب اللوزتين والزائدة الدودية والتهاب حوض الكلي – الدرن.

 

 

  • أمراض الحساسية والجلدية والطفيليات.
  • العدوي بالفيروسات.
  • الأورام الخبيثة وسرطان الدم.

 

أسباب النقص في عدد كريات الدم البيضاء:

 

 

  • العدوي ببعض الفيروسات.
  • فشل النخاع العظمي.
  • التيفود والباراتيفود.

المعدل المرجعي :

 

 

 

الفئة النسبة / مم 3 البالغين

4000 – 11.000 / مم3

أطفال( عام )

6000 – 18.000 / مم3

أطفال (4 – 7 أعوام)

5000 – 15.000 / مم3

أطفال (8 – 12 عام)

4.500 – 13.500 / مم3

 

 

 

 

 

مع فائق احترامى للجميع

أنواااااااااااع التحاليل الطبيبة

أنواااااااااااع التحاليل الطبيبة

المؤلف Mohammed Shedeed‏ في تحاليل طبيةد

General Checkup Profile (الفحص الدوري الشامل )

Complete Blood Count (CBC), Erythrocyte Sedimentation Rate (ESR), Fasting Blood Sugar(FBS), Uric Acid, Creatinine, Urea, SGOT, SGPT, Cholesterol, Triglycerides, HDL/LDL, Urine , Stool.

 

Liver Functions Profile (وظائف الكبد)

Bilirubin (Total & Direct), SGOT , SGPT, GGT, Alkaline phosphatase, Total protein, Albumin, A/G, Prothrombin time.

 

Kidney Function Profile (وظائف الكلية)

Urea, Creatinin, Uric acid, Urine, Sodium (Na), Potassium (K), Osmolality, Microalbuminuria.

 

Cardiac Profile (أنزيمات القلب)

Troponin I, CK (MB & Total), SGOT, LDH, CK isoenzymes, Myoglobin

 

Lipid Profile (شحوم الدم)

Total lipids, Cholesterol, Triglycerides, HDL/LDL.

 

Diabetes Profile (تحاليل السكر)

Initial diagnosis: Blood sugar curve.

 

Follow up:

l Fasting Blood Sugar (FBS), 2 Hours Post Prandial (2 HPP).

l Every 3 Months: Glycosylated Hemoglobin (GHB), Microalbuminuria.

l Yearly: General Checkup Profile.

l Other tests: Insulin, Anti Islet cell antibody, C-peptide.

 

Osteoporosis (هشاشة العظام)

Serum Cacium (Total & Ionized), Urinary Calcium, Alkaline phosphatase,

Para Thyroid Hormone (PTH intact), Osteocalcin, DPD, Betacrosslaps (CTX).

 

Rheumatology Profile (الأمراض الروماتيزمية)

ANA, AntiDNA, Uric acid, Erythrocyte Sedimentation Rate (ESR), C-Reactive Protein (CRP quantitative), Rheumatoid Factor(RF quantitative).

 

Autoimmune Diseases (أمراض المناعة الذاتية)

RF quantitative, CRP quantitative, Complement (C3, C4) Circulating Immune.

Synovial Fluid Aspirate for C/S if present.

Autoantibodies: ANA, DNA (single & double stranded), ASMA, RNP, AMA, SCL-70, SSA (Ro), SSB(La), ANCA, LKM ,JO-1

Anti Cardiolipin Total (IgG & IgM , Antisperm antibody (IgTotal, IgG, IgA)

 

Organ-Specific Tumor Markers (دالات الأورام)

Prostate: PSA (Free/Total), PAP

Tests: B-HCG, AFP

Breast: CA15.3, CA125 , CEA

Kidney: Erythropoietin.

Pheochromocytoma: VMA, Metanephrine

Cervix/Uterus: CEA

Ovary: CA125, B-HCG

Liver:AFP, CEA, CA19.9, Ferritin

Pancreas: CA19.9, CEA, CA125, Amylase.

GIT: CEA, CA19-9

Gastrinoma: Gastrin.

Lung:CEA

Thyroid: Calcitonin, CEA, Thyroylobulin

Pituitary: ACTH, GH, PRL

Neuroblastoma: VMA

 

Drug Monitoring (قياس المعايرات الدوائية)

l Lithuim (المهدئات العصبية)

l Digoxin (أدوية القلب)

l Cyclosporing Tacrolimus (أدوية منع طرد الأعضاء)

l Antiepileptics (أدوية الصرع)

Depakene, Tegretol, Phenytoin, Phenobarbital.

 

Drug Abuse Profile (المخدرات)

Cannabinnoids, Barbiturates, Benzodiazepines, Opiates, Cocaine.

 

Hormones (الهرمونات)

Thyroid: (الغدة الدرقية)

T3 (Free & Total), T4 (Free & Total), TSH, 3rd Generation

Thryroid Autoantibodies.

 

Parathyroid: (الغدة الجار درقية)

PTH intact.

 

Infertility (male): (العقم عن الرجال)

Semen, FSH, LH, PRL, E2, Testosterone (free & total).

Testosterone before and after Pregnyl, Inhbin B.

 

Infertility (femal): (العقم عن النساء)

FSH , LH, PRL, E2, Progesterone, Testosterone (Free & Total), Inhbin B..

 

Hirsutism : (الشعر الزائد عند الإناث)

FSH, LH, PRL, Testosterone (free & total), DHT, DHEA-S, DHEA,

17-OH Progestrone, Androstendione

Stimulation tests by Synechten

Suppression test by Dexamethasone

 

 

 

Cushing/Addison : متلازمة كوشنج ومرض أديسون

Cortisol (a.m./ p.m), Urinary free cortisol, ACTH.

Dexamethasone Supression

Synacthen Stimulation.

 

Acromegaly: ضخامة الأعضاء

Growth hormone basal, Growth hormone suppression (glucose), IGF-1, IGF-BP.

 

Short Stature : قصر القامة

Growth stimulatino by Clonidine & Insuline IGF-1, IGF-BP.

 

Feto-Placental Function : الوظيفة الجنينية المشيمية

B-HCG, Estriol (E3).

 

Hyertension: ضغط الدم المرتفع

VMA, Metanephreane.

 

Triple Markers for Down’s Synd. دالالات مرض الطفل المنغولي

AFP, HCG, Estriol E3, Triple test.

 

Trace Elements العناصر النادرة

Copper, Zinc, Lead.

 

Anaemia Screen تحاليل الانيميا

Complete Blood Count (CBC) , Reticulocytic count.

 

Anemia Investigations تحاليل الانيميا

l Normocytic anemia: Reticulocytic count

l Macrocytic anemia: Megaloblastic (B12, Folate), Non Megaloblastic (Liver functions, alcohol etc…)

l Microcytic anemia: Serum Iron, TIBC, Ferritin.

l Hemolytic Profile: Bilirubin (total & direct), Hemoglobin electrophoresis, Coomb’s test, Cold Agglutinin, Osmotic Fragility.

 

Hemostatic Screen (تحاليل تجلط الدم)

Bleeding TIme (BT). Cloting Time (CT), Prothombin Time(PT), Partial Thromboplastin time(PTP).

 

Specific Hemostatic Tests (تحاليل خاصة بتجلط الدم)

PTT, Lupus Anticoagulant,Prothrombin Time, Fibrinogen, Factor Assays

 

Hypercoagulable Thrombotic States (تحاليل التجلط الزائدة)

PTT, Protien C, Protien S, Fibringoen, Anti THrombin III, Platelet count, Lupus Anticoagulant.

 

DIC Screen (تحاليل تجلط الدم داخل الأوعية)

Anti Thrombin III, PTT, PT, Thrombin Time, FDPs, Fibrinogen, Factor Assay, Platelet count, D-Dimer.

 

 

 

Hepatitis markers:

Hepatitis A (HAV):

HA V IgM, HAV total.

Hepatitis B(HBV):

HbsAb, HBc total,

HbeAg, HbeAb,

HBV-DNA by PCR

Hepatitis C(HCV):

HCV- Abs

HCV-RNA(quantitative) by PCR.

Autoimmune heptitis: ANA, ASMA, AMA, LKM.

 

Parasitoloby (الطفيليات)

l Toxoplasma IgM, IgG

l Entamoebla stool examination

l Giardia stool examination

l Malaria film (thick & thin), serology

l Hydatid serology

 

Microbiology (الميكروبيولوجي)

l Tuberculosis – الدرن:

Film, Culture

l Brucella:

Serology, blood culture

l Chamydia:

Antibody

l Syphilis: الزهري

TPHA, VDRL, RPR

l Helicobacter:

Serology

l Anaerobes: البكتريا اللاهوائية

Blood Culture & Antibiogram

l Routine Culture for:

Urine, stool, prostatic secreation, pus, uretheral discharge, vaginal discharge, ear discharge, conjunctival discharge.

 

Allergy الحساسية

IgE Total.

 

Chronic Diarrhoea -الاسهال المزمن

Stool culture & sensitivity, D-Xylose, S. Transferrin.

 

Fever of unknown origin الحمى غير المعلومة المصدر

Complete Blood Count(CBC), Erythrocyte Sedimentation Rate (ESR), C-Reactive Protein (CRP), Stool and Urine examination and culture, Blood culture, Widal test, Antinuclear antibody (ANA).

 

Premarital Checkup تحاليل ما قبل الزواج

Male: Semen examination, Random blood sugar, Blood group & Rh,

Hemoglobin electrophoresis.

Femal: Toxo IgG & IgM, Random Blood Sugar, Blood group &Rh,

Hemoglobin electrophoresis.

 

Repeated Abortion الاجهاض المتكرر

l Infections : TORCH (IgG & IgM).

l Hormones: Proclain, LH & Progesterone (in the middle of hte luteal phase).

l Autoantibodies: ANA, dsDNA, Anticardiolipin IgG & IgM, Lupus anticoagulant

Hepatitis B

 

How is it used?

Hepatitis B tests may be used for a variety of reasons. Some of the tests detect antibodies produced in response to HBV infection; some detect antigens produced by the virus, and others detect viral DNA.

Generally, one set of tests is used to determine the cause of acute symptoms while another set of tests may be used after a diagnosis is made, to monitor possible progression of the disease, to detect chronic infection and/or carrier status.

The items below list the main uses for HBV tests:

  • To detect acute hepatitis B infection: hepatitis B surface antigen (HBsAg), hepatitis B core antibody (anti-HBc), IgM and sometimes hepatitis B e antigen (HBeAg)
  • To diagnose chronic HBV hepatitis: HBsAg, hepatitis B virus (HBV) DNA, and sometimes HBeAg
  • To monitor chronic hepatitis B infection and its treatment: HBsAg, hepatitis B e antigen (HBeAg), hepatitis B surface antibody (anti-HBs) IgG, hepatitis B e antibody (anti-HBe) IgG and HBV DNA
  • To detect previous exposure to hepatitis B, in a person who is immune compromised (when the virus can become reactivated): hepatitis B core antibody (anti-HBc) total and anti-HBs

Some of the secondary reasons to perform testing include: to screen for hepatitis B infection in at-risk populations or in blood donors, to determine if someone is a carrier, to detect previous infection (with subsequent immunity), and to determine if immunity has developed due to vaccination.

Some of the tests used to screen for infection may be performed as part of an acute viral hepatitis panel in conjunction with tests for other hepatitis viruses, including hepatitis A (HAV) or hepatitis C (HCV).

When is it ordered?

 

Hepatitis B tests may be ordered when someone has signs and symptoms associated with acute hepatitis to determine if they are due to infection with HBV. Some of these include:

  • Fever
  • Fatigue
  • Loss of appetite
  • Nausea, vomiting
  • Abdominal pain
  • Dark urine
  • Pale stools
  • Joint pain
  • Jaundice

Hepatitis B tests may be done as follow up when routine tests results such as ALT and/or AST are elevated. Sometimes acute forms of hepatitis may be detected this way since they may cause only mild symptoms that can be confused with the flu. Chronic hepatitis more often has no symptoms and is more commonly detected when routine test results are abnormal.

A test for hepatitis B surface antigen (HBsAg) may be used for screening when someone falls into one of the high-risk categories for chronic hepatitis B. In September 2008, the CDC revised it guidelines and recommends the following groups be tested for HBsAg:

  • People who are possible source of infection through accidental cuts, needlesticks, etc. in health care workers
  • People born in areas of the world that have a greater than 2% prevalence of HbsAg (for example, much of Asia and Africa)
  • People born in the US but were not vaccinated and whose parents are from an area with greater than 8% prevalence of HbsAg
  • Men who have sex with men
  • People who have elevated liver enzymes (ALT and AST) with no known cause
  • People with certain medical conditions that require that their immune system be suppressed
  • Pregnant women
  • People who are in close contact with someone infected with HBV
  • Those infected with HIV

In addition, some states in the US recommend that people who are in contact with the public and who are a possible source of infection through accidental cuts, scrapes, etc. be screened.

When hepatitis B tests are used to monitor people with chronic hepatitis B infections, they may be performed on a regular basis. Hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) are usually measured about every 6 months to a year, since in some people HBeAg (and, less commonly, HBsAg) will go away on their own. In those who are being treated for chronic HBV, HBeAg and HBV DNA can be used to determine whether the treatment is successful. HBV DNA will fall, usually to undetectable levels, with successful treatment. If HBeAg was positive before treatment and becomes negative, then treatment may sometimes be stopped after a further period of treatment, and both it and HBV DNA may remain undetectable. If HBeAg was negative before treatment or remains positive, then treatment is usually continued.

All donated blood is tested for the presence of the HBsAg before being distributed for transfusion.

Is there anything else I should know?

 

Even if you don’t have symptoms, an HBV infection can damage your liver and you can spread the infection to others. For this reason, it is important to get tested if you think you have been exposed to HBV.

Hepatitis D (HDV) is another virus that can cause liver infections, but only if hepatits B is also present. A person may become infected with both viruses at the same time (a co-infection) or may first be infected with hepatitis B and then become infected with HDV (a superinfection). In the U.S., the incidence of HDV is low. There is no vaccine for HDV, but since it causes infections only in the presence of HBV, it may be prevented with the HBV vaccine.

HCV

How is it used?

 

Hepatitis C tests are used to detect and diagnose an infection and/or to monitor the treatment of hepatitis C virus (HCV). Tests are used to detect the condition if a person:

  • Has been exposed to someone with HCV
  • Participates in high risk behaviors such as injecting street drugs
  • Has abnormal liver function tests
  • Has symptoms associated with liver disease, such as jaundice, dark urine, nausea, or unexpected weight gain or loss

The following tests may be used to screen for and/or detect HCV:

  • Anti-HCV test detects the presence of antibodies to the virus, indicating exposure to HCV. This test cannot distinguish between someone with an active or a previous HCV infection. Usually, the test is reported as “positive” or “negative.” There is some evidence that if the test is “weakly positive,” it may be a false positive. The Centers for Disease Control and Prevention (CDC) suggests that weakly positive tests be confirmed with the HCV RIBA test before being reported.
  • HCV recombinant immunoblot assay (RIBA) test is an additional test ordered to confirm the presence of HCV antibodies. In most cases, it can tell if the positive anti-HCV test was due to exposure to HCV (positive RIBA) or represents a false signal (negative RIBA). In a few cases, the results cannot answer this question (indeterminate RIBA). Like the anti-HCV test, the RIBA test cannot distinguish between a current or past infection.

The following tests may be used to diagnose a current infection and to guide and monitor treatment:

  • HCV RNA test, Qualitative may be used to distinguish between a current or past infection. It is reported as a “positive” or “detected” if any HCV viral RNA is found; otherwise, the report will be “negative” or not detected.” It may also be ordered after HCV treatment is complete to see if the virus has been eliminated from the blood. These tests are seldom used any more.
  • HCV Viral Load (HCV RNA test, Quantitative) detects and measures the number of viral RNA particles in the blood. Viral load tests are often used before and during treatment to help determine response to treatment by comparing the amount of virus before and during treatment (usually at several time points in the first three months of treatment). Successful treatment causes a decrease of 99% or more (2 logs) in viral load soon after starting treatment (as early as 4-12 weeks) and usually leads to viral load being not detected even after treatment is completed. Some newer viral load tests can detect very low amounts of viral RNA.
  • Viral genotyping is used to determine the kind, or genotype, of the HCV virus present. There are 6 major types of HCV; the most common (genotype 1) is less likely to respond to treatment than genotypes 2 or 3 and usually requires longer therapy (48 weeks versus 24 weeks for genotype 2 or 3). Genotyping is often ordered before treatment is started to give an idea of the likelihood of success and how long treatment may be needed.

^ Back to top

When is it ordered?

 

The CDC recommends screening for HCV infections in the following cases:

  • If you have ever injected illegal drugs
  • If you received a blood transfusion or organ transplant before July 1992*
  • If you have received clotting factor concentrates produced before 1987
  • If you were ever on long-term dialysis
  • For children born to HCV-positive women
  • For health care, emergency medicine, and public safety workers after needlesticks, sharps, or mucosal exposure to HCV-positive blood
  • For people with evidence of chronic liver disease

*The blood supply has been monitored in the U.S. since 1992, and any units of blood that test positive for HCV are rejected for use in another person. The current risk of HCV infection from transfused blood is about 1 case per two million transfused units.

Most people newly infected with HCV have no symptoms or ones that are so mild that they rarely prompt a person to visit a doctor and get tested for HCV. However, about 10-20% of people may experience symptoms such as fatigue, pain in the abdominal area, decreased appetite, and jaundice and may be tested for HCV.

A positive anti-HCV test may be confirmed with an HCV RIBA test, especially when the anti-HCV test is “weakly positive.” Many physicians do not use RIBA since it still does not determine if a person is currently infected. Quantitative HCV-RNA is often ordered when the antibody test is positive to see if the infection is still present. HCV viral load and genotyping may be done when treatment is planned; viral load may be ordered periodically to monitor response to treatment and at the completion of treatment to evaluate its effectiveness.

^ Back to top

What does the test result mean?

Interpretation of the HCV tests is shown in the table below. In general, if the HCV antibody test is strongly positive, then someone has likely been infected at some time with hepatitis C. If the HCV RNA test is positive, then the person has a current infection. If no HCV viral particles are detected, then the person either does not have an active infection or the virus is present in very low numbers.

Is there anything else I should know?

 

HCV antibodies usually do not appear until several months into an infection but will always be present in the later stages of the disease.

About 25% of those with HIV/AIDS also have an HCV co-infection, and their liver disease is likely to progress at an accelerated rate.

PSA

How is it used?

 

If prostate cancer is diagnosed, the total PSA test may be used as a monitoring tool to help determine the effectiveness of treatment. It may also be ordered at regular intervals after treatment to detect recurrence of the cancer.

The total PSA test and digital rectal exam (DRE) may be used to screen both asymptomatic and symptomatic men for prostate cancer. If either the PSA or the DRE are found to be abnormal, then the doctor may choose to follow this testing with a prostate biopsy and perhaps imaging tests, such as an ultrasound. If the DRE is normal but the PSA is moderately elevated, the doctor may order a free PSA test to look at the ratio of free to total PSA. This can help to distinguish between prostate cancer and other non-cancer causes of elevated PSA. Since the total PSA test can be elevated temporarily for a variety of reasons, a doctor may order another PSA a few weeks after the first to determine if the PSA is still elevated.

Currently there is no consensus about using the PSA test to screen for prostate cancer in asymptomatic men. While prostate cancer is a relatively common type of cancer in men, it is an uncommon cause of death. In cases where the cancer appears to be slow-growing, the doctor and patient may decide to monitor its progress rather than pursue immediate treatment (called “watchful waiting”). Total PSA levels may be ordered at intervals to monitor the change in PSA over time.

The complexed PSA (cPSA) is a relatively new test that may be ordered, along with the DRE, as an alternative to the total PSA. There is hope that this test could be more specific than the total PSA – better at detecting cancer-related PSA, but findings have been mixed and its ultimate clinical utility has yet to be established. The cPSA is an option that doctors can discuss with their patients. Its use may expand and/or be better defined as additional studies are conducted and findings are reported.

^ Back to top

When is it ordered?

 

There is currently no consensus among the experts about when the PSA test should be ordered to screen asymptomatic males. Over-diagnosing, identifying cases of prostate cancer that may never cause significant health problems, must be balanced against missing the detection of aggressive cancers.

National organizations reflect this lack of consensus, giving conflicting recommendations on routine PSA-based screening of asymptomatic men. Some organizations such as the American Urological Association recommend screening, while others such as the U.S. Preventive Services Task Force feel that the harms associated with over-diagnosis and over-treatment outweigh the potential benefits. The American Cancer Society (ACS) recommends that men discuss the advantages and disadvantages of PSA-based screening for prostate cancer with their doctor before making an informed decision about whether to be screened or not.

For men who wish to be screened, the ACS recommends that healthy men of average risk consider waiting to get tested until age 50; for those at high risk, such as American men of African descent and men with a family history of the disease, the recommendation is to consider beginning testing at age 40 or 45. The American Urological Association recommends a baseline PSA and DRE at age 40. (See Screening Tests for Adults (30-49): Prostate cancer and Screening Tests for Adults (50 and Up): Prostate cancer for details on screening recommendations.)

The total PSA test and DRE may also be ordered when a man has symptoms that could be due to prostate cancer, such as difficult, painful, and/or frequent urination, back pain, and/or pelvic pain. Since these symptoms are seen with a variety of other conditions, including infection and prostatitis, the doctor will also frequently order other tests, such as a urine culture. Some of these conditions can themselves cause temporary increases in PSA levels. If a total PSA level is elevated, a doctor may order a repeat test a few weeks later to determine whether the PSA concentrations have returned to normal.

A free PSA is primarily ordered when a man has a moderately elevated total PSA. The results give the doctor additional information about whether the person is at an increased risk of having prostate cancer and help with the decision of whether to biopsy the prostate.

The total PSA may be ordered during treatment of men who have been diagnosed with prostate cancer to verify the effectiveness of treatment and at regular intervals after treatment to monitor for cancer recurrence. It is also ordered at regular intervals when a man with cancer is participating in “watchful waiting” and not currently treating his prostate cancer.

^ Back to top

What does the test result mean?

 

 

PSA test results can be interpreted a number of different ways and there may be differences in cutoff values between different laboratories. The normal value for total PSA is considered to be less than 4.0 ng/ml (nanograms per milliliter of blood). There are some that feel that this level should be lowered to 2.5 ng/ml in order to detect more cases of prostate cancer. Others argue that this would exacerbate over-diagnosing and over-treating cancers that are not clinically significant.

There is agreement that men with a total PSA level greater than 10.0 ng/ml are at an increased risk for prostate cancer (more than a 67% chance, according to the ACS). Levels between 4.0 ng/ml and 10.0 ng/ml may indicate prostate cancer (about a 25% chance, according to the ACS), BPH, or prostatitis. These conditions are more common in the elderly, as is a general increase in PSA levels. Concentrations of total PSA between 4.0 ng/ml and 10.0 ng/ml are often referred to as the “gray zone.” It is in this range that the free PSA is the most useful. When men in the gray zone have decreased levels of free PSA, they have a higher probability of prostate cancer; when they have elevated levels of free PSA, the risk is diminished. The ratio of free to total PSA can help the doctor decide whether or not a prostate biopsy should be performed.

When the complexed PSA (cPSA) test is used as a screening tool, increased levels may indicate an increased risk of prostate cancer, while lower levels indicate a decreased risk.

In addition to the introduction of the free PSA and cPSA tests, there have been efforts to increase the usefulness of the total PSA as a screening tool. They include:

  • PSA velocity. This is the change in PSA concentrations over time. If the PSA continues to rise significantly over time (at least 3 samples at least 18 months apart), then it is more likely that prostate cancer is present. If it climbs rapidly, then the affected person may have a more aggressive form of cancer.
  • PSA doubling time. This is another version of the PSA velocity. It measures how rapidly the PSA concentration doubles.
  • PSA density. This is a comparison of the PSA concentration and the volume of the prostate (as measured by ultrasound). Men with larger prostates tend to produce more PSA, so this factor is an adjustment to compensate for the size.
  • Age-specific PSA ranges. Since PSA levels naturally increase as a man ages, it has been proposed that normal ranges be tailored to a man’s age.

During treatment for prostate cancer, the PSA level should begin to fall. At the end of treatment, it should be at very low or undetectable levels in the blood. If concentrations do not fall to very low levels, then the treatment has not been fully effective. Following treatment, the PSA test is performed at regular intervals to monitor the person for cancer recurrence. Since even tiny increases can be significant, those affected may want to have their monitoring PSA tests done by the same laboratory each time so that testing variation is kept to a minimum.

A relatively new test called “ultrasensitive PSA” (USPSA) has been reported. It has been suggested that this test may be useful in monitoring for persistence or recurrence of cancer after treatment. This test detects PSA at much lower levels than the traditional test. It has been suggested that increases in PSA due to the persistence or return of cancer can be identified much sooner with this test. However, results of this test must be interpreted with caution. Because the test is very sensitive, there can be an increase in PSA levels from one time to the next even when no cancer is present (false positive).

^ Back to top

Is there anything else I should know?

 

Since the DRE can cause a temporary elevation in PSA, the blood is usually collected prior to performing the DRE.

Prostate manipulation by biopsy or resection of the prostate will significantly elevate PSA levels. The blood test should be done before surgery or six weeks after manipulation.

Rigorous physical activity affecting the prostate, such as bicycle riding, may cause a temporary rise in PSA levels. Ejaculation within 24 hours of testing can be associated with elevated PSA levels and should be avoided.

Large doses of some chemotherapeutic drugs, such as cyclophosphamide and methotrexate, may increase or decrease PSA levels.

In some men, PSA may rise temporarily due to other prostate conditions, especially infection. A recent study found that in about half of men with a high PSA, values later return to normal. Some authorities recommend that a high PSA should be repeated, between 6 weeks and 3 months after the high PSA, before taking any further action. Some physicians will prescribe a course of antibiotics if there is evidence that there is infection of the prostate.

%d مدونون معجبون بهذه: