CLINICAL HEMATOLOGY

Hematological samples are anticoagulated ones. So, the following precautions must be followed:

• Select the suitable anticoagulant for test
• Ensure proper ratio of the anticoagulant to the sample
• Allow good mixing of samples

Test Name

        Sample

Test Interference

Remarks

• Antithrombin III

Citrated blood

Increases by anabolics

Decreases by Heparin

• Bleeding time (BT)

Increases by Aspirin,Penicillin G,non steroidal anti-inflammatory drugs

• Blood group (ABO)

Citrated blood

Gram negative septicaemia

• Bone marrow aspiration and examination

Contact Lab

• · Bone marrow trephine biopsy

Contact Lab

• Complete blood count (CBC)

EDTA-anticoagulated sample

Send to the lab within 2 hours

Follow up of anemia by Hb and reticulocyte count after one week from start of supportive therapy

Bi or pancytopneia recommend BM examination.

• Coomb’s Test (Direct)

EDTA anticoagulated blood

• Coomb’s Test (Indirect)

Serum sample (clotted blood)

Previous blood transfusion must be excluded

• Cytogenetic Analysis (conventional )

Heparinized BM sample

• Cytogenetic Analysis (FISH)

• Cytochemistry (MPO, NAP score)

Contact  the Lab

• D-dimer

Order a special Lab-supplied tube

• Erythrocyte sedimentation rate (ESR)

Citrated sample in the ratio 1:4 (blood should reach the mark on the tube)

Increases by oral contraceptives, vitamin A , phenytoin.

Decrease by corticisteroids, salicylate, quinidine, streptomycin, tetracyclins, sulfonamides.

• Factor Assay (VIII, IX)

Citrated sample (1:9) (blood sample should reach the mark on the tube)

 Drugs interacting with anticoagulant therapy as some antibiotics

Prenanlytic precautions must be followed:

Ratio of blood to the anticoagulant

Timing of the sample related to therapy

Immediate assay

• Ferritin

 Morning serum, to exclude diurnal variation

Iron therapy and recent transfusion must be excluded

• Fibrin degradation products (FDPs)

Order a special Lab-supplied tube

High titre of Rheumatoid factor

• Fibrinogen

Order a special Lab-supplied tube

• G6PD (qualitative)

EDTA blood  sample

Recent blood transfusion must be excluded

Recent hemolytic crises

Done 3^rd week after hemolytic attack

• G6PD (quantitative)

EDTA blood sample

Same as above

Same as above

Test Name

        Sample

Test Interference

Remarks

• Ham’s test (acidified serum test)

• Hemoglobin electrophoresis

EDTA blood sample

Patients' CBC, blood incices should be supplied , good family history. Recent blood transfusion should be excluded (at least 2 weeks)

• Immunophenotyping panel

Contact the Lab

• Immunophenotyp-ing (eachmonoclonal)

Contact the Lab

• Iron

Serum , morning sample in a plastic tube

Increases by iron therapy, recent blood transfusion, aspirin, corticosteroids, chloramphenicol.

Decease by stress and sleep deprivation

• Iron stain for BM

EDTA BM sample

• Lupus anticoagulant

Citrated blood

Lab supplied tube

• Malaria and Filaria blood film

EDTA anticoagulated blood taken during the attack of fever

Fresh direct blood film (EDTA blood)

In between attacks examine for the presence of antibodies in serum

• Neutrophil alkaline phosphatase (NAP) score

Fresh direct blood film

Decreases by EDTA

• Osmotic fragility testing

Fresh heparinized blood

(within 2 hrs)

Malaria infection

Assay done within 6 hours

• Platelet aggregation (ADP, Ristocetin)

Citrated blood+ EDTA blood

Lipemia,aspirin,diuretics,indo-methacin, nitrofurantoin,penicillin, antidepressants, anesthetics

Aspirin or antiplatelet drugs should be discontinued 15 days before the test

• Platelet count

Fresh EDTA sample

Epinephrine, analgesics, aspirin, salicylate, codeine, sulfonamides, penicillin, diuretics, insulin, hypoglycemics

Manual platelet count is requested only in cases of suspected platelet function abnormality or high PDW as in Bernard Soulier disease.

• Prothrombin time (PT)

Citrated sample (1:9) (blood sample should reach the mark on the tube)

Immediate assay

Anabolic steroids, antibiotics, , quinines,cyclophosphamide, laxatives, halothane, heparin, methotrexate, niacin, pyrazinamide, thiazides.

  Chloralhydrate, chloramphenicol,glucagons enhance the effect of oral anticoagulant.

Barbiturates, carbamazepine, phenytoin suppress the effect of oral anticoagulant.

Prolonged storage at 4◦C, poor venipuncture, hemolyzed samples  may shorten PT.

Prenanlytic precautions must be followed:

 Ratio of blood to the anticoagulant

Timing of the sample related to therapy.

Used for follow up of oral anticoagulants

• Partial thromboplastin time (PTT)

Citrated sample (1:9) (blood sample should reach the mark on the tube)

Immediate assay

Traumatic venipuncture shorten  shorten PTT

Following a recent thrombotic event the PTT is often below normal, and responds slowly to anti vit K drugs

• Protein C

Citrated blood

• Protein S

Citrated blood

• Reticulocyte count

Fresh EDTA sample

Immediate assay

Decrease by high glucose level

Reticulocyte index, corrected reticulocyte count must be requested in anemic patients

• Rh type

EDTA blood sample

• Sickle test

EDTA blood sample

Indicated during suspected crisis

• Thrombin time

Citrated blood sample

Lab supplied tube

Immediate assay

• Transferrin

Serum sample

• Total iron binding capacity (TIBC)

 Morning serum, to exclude diurnal variation

Iron therapy and recent transfusion must be excluded

• Von-Willibrand factor
  • Citrated sample (1:9) (blood sample should reach the mark on the tube)
  • Prenanlytic precautions must be followed:

-       Ratio of blood to the anticoagulant

-       Timing of the sample related to therapy

-       Immediate assay

-       Other interfering drugs interacting with anticoagulant therapy as some antibiotics.

• White cell count (WBCs)with differential

EDTA blood