Bleeding Time (BT)

Bleeding Time (BT)

 

Normal Range

3 – 9.5 minutes

Indications and Interpretations         

·        BT is functional test of primary hemostasis

·        BT is single screening test for platelet functional or structural disorders, acquired (e.g. uremia) or congenital

·        Normal BT without suggestive history usually excludes platelet dysfunction. However, a normal BT does not rule out significant defect; with clinical suspicion platelet aggregation should be performed

·        To work up for coagulation disorders in patients, having history of excess bleeding even with normal platelet count.

·        Normal in all other disorders of coagulation except von Willebrand's disease deficiency and some cases of very low plasma fibrinogen.

·        May be useful to monitor treatment of active hemorrhage in patients with prolonged BT due to uremia, Von Willebrand's disease, congenital platelet function abnormalities or severe anemia.

·        No value in performing BT if platelet count < 100,000/cumm as BT is usually prolonged. Prolonged BT with platelet count > 100, 000/cumm usually indicates impaired platelet function (e.g. due to aspirin) or von Willebrand's disease.   

·        Even with a prolonged BT, blood loss does not exceed that of patients with normal BT. Prolonged BT does not necessarily cause increased bleeding.

·        BT increased out of proportion to platelet count suggests von Willebrand's disease or qualitative platelet defect.

Usually prolonged in 

Thrombocytopenia: Platelet count < 100,00/cumm and usually < 80,000/cumm before BT becomes abnormal and < 40,000/cumm before abnormality becomes pronounced.

Platelet function disorders

Hereditary: Von Willebrand's disease, deficient release of platelet glycoproteins, gray platelet syndrome, hereditary hemorrhagic telangiectasia

Acquired: Drugs (aspirin, non- steroidal anti-inflammatory drugs [ NSAIDs], antimicrobials, anticoagulants, anesthetic, calcium channel blockers, β – blockers, phenothiazine, antidepressants), uremia, fibrin degradation products (e.g. disseminated intravascular coagulation [DIC], liver disease, fibrinolytic therapy, immune thrombocytopenias, myeloproliferative disease, vascular disorders, amyloidosis, viral infections, scurvy.

Usually normal in

Hemophilia, severe hereditary hypoprothrombinemia or hypofibrinogenemia.

Erythrocyte Sedimentation Rate (ESR)

Erythrocyte Sedimentation Rate (ESR)

Introduction

ESR is the rate at which RBC's settle down when blood, to which anticoagulant is added, is allowed to stand in a narrow tube for one hour expressed in millimeters of clear plasma at the end of 1st hour. Sedimentation rate depends on various factors like; rouleaux formation (Rouleaux formation is directly proportional to concentration of fibrinogen and globulin in plasma. It is retarded by albumin); viscosity of plasma (ESR decreases if viscosity increases); ratio of cells to plasma (decreased ratio leads to increase Rouleaux formation); nature of anticoagulant used.

 

 

Normal Range (mm in 1 hr)
Westergren		Wintrobe's
Males	Females	Males	Females	Children	Newborns
0 –13	0 –20	0 –10	0 -15	0 – 13	0 -2

 

Increased in

Tissue damage or inflammation, anemia, any toxic or infective condition (acut or chronic), malignancies, nephrosis, physiological increase in females, pregnancy increase in temperature.

            Decreased in

Polycythemia, leukemia, hypofibrinogenemia, pernicious anemia, congestive heart failure (CHF), Protein shock (e.g. burns, severe allergic reactions), physiological decrease in newborns, decrease in temperature.

Reticulocyte Count (RC)

Reticulocyte Count (RC)

Introduction

The reticulocyte count is a fairly accurate reflection of erythropoietic activity therefore their number increases whenever red blood cells (RBCs) are being rapidly manufactured.

Normal Range

Adults: 0.5 – 1.85 % of erythrocytes, absolute count – 29,000 – 87, 000/cu.mm.

Newborn: 2.5 – 6.5 %, falls to adult range by second week of life.

Indications

·        Diagnosis of inffective erythropoiesis or decreased RBC formation

·        Increase indicates effective RBC production used as: Index of therapeutic response to iron, folate or vitamin B12 therapy and blood loss; monitor treatment response after bone marrow suppression and transplantation; monitor response to erythropoietin therapy.

Increased in

 After blood loss or increased RBC destruction, after iron therapy, after specific therapy for megaloblastic anemia and other hematologic conditions like polycythemia, metastatic carcinoma in bone marrow.

 Decreased in   

Ineffective erythropoiesis or decreased RBC formation (severe autoimmune type  of hemolytic disease, megaloblastic disorders), alcoholism, myxedema.