
Dear #medicine residents
When you are confronted with a High Platelet Count
How to make sense out of it
Keep reading
#medtwitter #MedEd #medstudenttwitter #medicalstudents


Common Things are Common First!
Think Secondary Causes

1️⃣ Infection
2️⃣ Inflammation
3️⃣ Recent Surgery / Trauma
4️⃣ Medications: Steroids
5️⃣ Connective Tissue Disorders
6️⃣ Malignancy


When You Assess Clinically / Think Logically
1️⃣ Take a Good History
2️⃣ Medications History
3️⃣ Bleeding / Menstrual History
4️⃣ Microvascular Symptoms
5️⃣ Any Previous Surgery/VTE/Stroke
6️⃣ Red Flag Symptoms / B Symptoms
7️⃣ Examination: Assess for Organomegaly/Lymphadenopathy



Request The following Investigations as appropriate
1️⃣ Full Blood count
2️⃣ Blood Film
3️⃣ Urea & Electrolytes
4️⃣ Liver Function Tests
5️⃣ CRP / LDH / ESR / Autoimmune Profile
6️⃣ Ferritin / Iron Studies
7️⃣ Radiology i.e. CT Scan is needed


On a Blood Film
👉 If Hypochromic Microcytic/ Pencil Cells / Thrombocytosis ➡️ Likely IDA

👉If Reactive Features like Activated Neutrophils / Monocytes / High Platelets ➡️ Likely Infection

👉Anisothrombia / Eosinophila / Basophils ➡️ Possible MPD


Now above causes dont fit
Then Ask Yourself could this be Primary Myeloproliferative Disease
Then Do the Following
1️⃣ Assess Microvascular Symptoms (Pins/Needles - Hands or feet)
2️⃣ Any Previous VTE / Stroke
3️⃣ Send an Urgent EDTA Sample for JAK2/CALR/MPL
4️⃣ Refer to Haem


➡️ Urgent Referral Criteria

1️⃣ Persistent thrombocytosis >600 (>3mths apart), no reactive cause
2️⃣ Persistent thrombocytosis >450 in patients with an acute clot (arterial or venous)

➡️ Routine Referral

1️⃣ Persistent thrombocytosis >450 for at least 3 months (Nil Reactive)


I hope you've found this thread helpful.
Thank You for Reading :)

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You can read the unrolled version of this thread here: https://typefully.com/MorphologyAmigo/KU1AXI6
@nihardesai7 @bloodworkapp @eskazanae @acweyand @HermelinMD @KMirza @BloodScientist

Making Sense of High Platelet Count: Common Causes and Clinical Assessment


Dear #medicine residents
When you are confronted with a High Platelet Count
How to make sense out of it
Keep reading
#medtwitter #MedEd

Decoding High Platelet Count: Considerations and Assessment


Dear #medicine residents & #hematology Amigos
In the days of DOAC there is still some relevance left for Warfarin in certain indications
But how do we measure Warfarin
How do we Compute the INR
Lets explore in this thread
(Amended 🧵)
#medEd #medtwitter




1️⃣ Prothrombin Time was described by Quick in 1935
2️⃣ to as 'Quick's Prothrombin Time'
3️⃣ Time was developed to measure Prothrombin (Factor II)
4️⃣ was sensitive to abnormalities of factors VII, X, V, II [Prothrombin] and Fibrinogen [Factor 1]


1️⃣ (TPL) is derived from cell membranes and is a mixture of both phospholipids
2️⃣ Sources are Human, rabbit or Bovine
3️⃣ PT in an individual with deficiencies of clotting factors will vary with the type of Thromboplastin. This is called Sensitivity Index.


1️⃣ are performed in duplicate for each TPL and the mean for each pair of tests derived
 2️⃣ 20 normal donors not on anticoagulants and 60 patients who have been on oral anticoagulant treatment for at least 6 weeks are tested
3️⃣The mean of each pair of PT results are plotted


1️⃣Take The Highest Point on the yellow line marked A
2️⃣ The lowest Point on the yellow line is marked B
-The Top point where it meets the X Axis is point C
Now we need to Calculate the SLOPE which will compute the ISI

Slope=A to C Distance / B to C Distance


Now lets take a Simple Example
The Distance Between A to C is 100 mm
The Distance from B to C is 90mm

Ref TPL ISI lets say is 1.1
Lets Apply for Formula

Slope = 100 / 90 = 1.11

ISI Test TPL = ISI (Ref TPL) x Slope
                       = 1.1 X 1.1= 1.21




1️⃣ TPL should be chosen with ISI close to 1
2️⃣ Using a TPL with an ISI of 1.0 the PT can range from 15s - 35s but the INR is still in the therapeutic range
3️⃣ If the ISI of the TPL is 2.0 an increase in the PT from 15s to 30s results in an INR outwith the therapeutic range.


Lets Look at the INR 🥸
➡️PT ratio of a test sample compared to a normal PT corrected for the sensitivity of the TPL used in the test
➡️ INR=( PT Patient / PT of reference Plasma) x ISI

Step1️⃣INR= 23 / 12 = 1.91
Step2️⃣  1.91 Corrected for ISI
⚕️INR is 2.18



1️⃣The INR is used for monitoring patients on warfarin
2️⃣Should NOT be routinely used to assess severity of Liver dysfunction- PT is better for that
3️⃣Used in MELD score [Model for End-stage Liver Disease] or the Child-Pugh score




I hope you've found this thread helpful.

Follow me @MorphologyAmigo for more in the future
Kudos to Practical Haemostasis for still keeping all this stuff free to see and learn from :)
Thanks @Sampath22775591 for pointing out the appropriate correction

You can read the unrolled version of this thread here: https://typefully.com/MorphologyAmigo/9fWN3mj
@nihardesai7 @PriyaSriRajah @AbbasiMuqtadir @UsuarezMD @DoctorBhavsar @PeterItebimien

Measuring Warfarin: Exploring the INR


#AmigoThreads
Dear #medicine residents & #hematology Amigos
In the days of DOAC there is still some relevance left for Warfarin in certain indications
But how do we measure Warfarin
How do we Compute the INR
Lets explore in this thread
#medtwitter #meded



-The Prothrombin Time was described by Quick in 1935
-Referred to as 'Quick's Prothrombin Time'
-Prothrombin Time was developed to measure Prothrombin (Factor II)
-It was sensitive to abnormalities of factors VII, X, V, II [Prothrombin] and Fibrinogen [Factor 1]


-Thromboplastin (TPL) is derived from cell membranes and is a mixture of both phospholipids
-TPL Sources are Human, rabbit or Bovine
-The PT in an individual with deficiencies of clotting factors will vary with the type of Thromboplastin. This is called Sensitivity Index.



-PTs are performed in duplicate for each TPL and the mean for each pair of tests derived
-20 normal donors not on anticoagulants and 60 patients who have been on oral anticoagulant treatment for at least 6 weeks are tested
-The mean of each pair of PT results are plotted


-Take The Highest Point on the yellow line marked A
- The lowest Point on the yellow line is marked B
-The Top point where it meets the X Axis is point C
Now we need to Calculate the SLOPE which will compute the ISI

Slope=A to C Distance / B to C Distance


Lets Look at the INR 🥸
➡️PT ratio of a test sample compared to a normal PT corrected for the sensitivity of the TPL used in the test
➡️ INR=( PT Patient / PT of reference Plasma) x ISI

Step1️⃣INR= 23 / 12 = 1.91
Step2️⃣ 1.91 x 1.1 = 2.1
⚕️INR is 2.1



I hope you've found this thread helpful.

Follow me @MorphologyAmigo for more in the future

