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Table of Contents
Test your blood test interpretation and clinical reasoning skills with the following case studies.
For each case study, we encourage you to interpret the patient’s blood tests using a structured approach and formulate an overall impression of the results. This will be followed by a discussion on the clinical reasoning behind the case.
Case study 1
A 57 year old man presents to the emergency department with a two day history of fever and abdominal pain. He has a past medical history of hypertension on ramipril. On examination he appears jaundiced and has a tender right upper quadrant. His temperature is 38.5oC, heart rate 101 bpm and blood pressure 110/80 mmHg.
Interpret the patient’s blood tests using a structured approach. This will be followed by a discussion on the clinical reasoning behind the case.
Blood test results
Full blood count (FBC)
| Test | Result | Reference range |
| Haemoglobin (Hb) | 135 | ♂ 130 – 180 g/L ♀ 115 – 165 g/L |
| White cell count (WCC) | 19.78 | 3.6 – 11.0 x 109/L |
| Neutrophils | 15.8 | 1.8 – 7.5 x 109/L |
| Lymphocytes | 3.0 | 1.0 – 4.0 x 109/L |
| Monocytes | 0.6 | 0.2 – 0.8 x 109/L |
| Eosinophils | 0.3 | 0.1 – 0.4 x 109/L |
| Basophils | 0.08 | 0.02 – 0.10 x 109/L |
| Platelet count | 430 | 140 – 400 x109/L |
| Mean cell volume (MCV) | 92.1 | 80 – 100 fL |
Urea & electrolytes (U&Es)
| Test | Result | Reference range |
| Sodium (Na+) | 137 | 133 – 146 mmol/L |
| Potassium (K+) | 4.9 | 3.5 – 5.3 mmol/L |
| Urea | 10.2 | 2.5 – 7.8 mmol/L |
| Creatinine | 175 | ♂ 59 – 104 μmol/L ♀ 45 – 84 μmol/L |
| eGFR | 42 | >90ml/min/1.73m² |
Liver function tests (LFTs)
| Test | Result | Reference range |
| Alkaline phosphatase (ALP) | 320 | 30 – 130 U/L |
| Alanine aminotransferase (ALT) | 37 | ♂ <41 U/L ♀ <33 U/L |
| Aspartate aminotransferase (AST) | 52 | 1 – 45 U/L |
| Bilirubin | 72 | <21 μmol/L |
| Gamma-glutamyl transferase (GGT) | 160 | ♂ <60 U/L ♀ <40 U/L |
| Albumin | 37 | 35 – 50 g/L |
Amylase
| Test | Result | Reference range |
| Amylase | 140 | 28–100 U/L |
C-reactive protein (CRP)
| Test | Result | Reference range |
| CRP | 210 | <5 mg/L |
Bone profile
| Test | Result | Reference range |
| Corrected calcium | 2.5 | 2.2 – 2.6 mmol/L |
| Phosphate | 1.2 | 0.8 – 1.5 mmol/L |
| Alkaline phosphatase (ALP) | 320 | 30 – 130 U/L |
Coagulation screen
| Test | Result | Reference range |
| PT | 12 | 10 – 14 seconds |
| APTT | 32 | 24 – 47 seconds |
| Fibrinogen | 3.1 | 1.5 – 4.5 g/L |
Interpretation
| Test | Interpretation |
| FBC | WCC raised with a neutrophilic leukocytosis and borderline raised platelets |
| U&Es | raised creatinine and low eGFR suggesting either an AKI or a CKD |
| LFTs | obstructive picture with predominantly raised ALP, GGT and bilirubin |
| Amylase | borderline raised |
| CRP | significantly raised in keeping with an infection |
| Bone profile | raised ALP as seen in the LFTs |
| Coagulation | normal coagulation screen |
| Overall impression | ascending cholangitis |
Explanation
Full blood count (FBC)
Neutrophilic leukocytosis suggesting a bacterial infection. His platelets are borderline elevated which can be seen as part of an acute phase response.
Useful link: Geeky Medics | Full Blood Count | Interpretation Guide
Urea & Electrolytes (U&Es)
Raised creatinine and decreased eGFR here suggest an AKI or CKD. This would need to be compared to his most recent blood test. However, there is no indication in the stem that he suffers from chronic kidney disease. It is reasonable to assume in this case that he has an acute kidney injury likely driven by sepsis.
Useful link: Geeky Medics | U&Es | Interpretation Guide
Liver function tests (LFTs)
Most of the LFTs are deranged. However, it is the ALP, GGT and bilirubin which are most significantly raised, suggesting an obstructive jaundice.
Useful link: Geeky Medics | LFTs | Interpretation Guide
Amylase
The amylase is borderline raised which is a non-specific finding often seen with abdominal pathologies. An amylase of two to three times the upper limit of normal would raise the suspicion of pancreatitis.
CRP
This is significantly raised in keeping with an infective process.
Bone profile
The ALP is raised as seen in the LFTs. Serum alkaline phosphatase is derived from biliary epithelial cells as well as bones. A raised ALP in conjunction with a raised GGT and bilirubin suggest a biliary rather than orthopaedic pathology.
Useful link: Geeky Medics | Bone Profile | Interpretation Guide
Coagulation screen
Normal coagulation screen.
Useful link: Geeky Medics | Coagulation Screen | Interpretation Guide
Overall impression
This patient is presenting with right upper quadrant pain, jaundice and fever. This triad of symptoms is referred to as Charcot’s triad and is associated with ascending cholangitis (also known as acute cholangitis).
The full blood count shows a neutrophilia, suggesting a bacterial infection supported by a significantly elevated CRP. The LFTs show an obstructive picture which, combined with the RUQ tenderness and fever, indicate there is an infected and obstructed biliary system.
The patient’s vital signs indicate that he is significantly unwell with a fever and tachycardia. He is also relatively hypotensive, given his past medical history of hypertension.
This patient should be managed following the sepsis 6 approach with early broad spectrum IV antibiotics and IV fluids. Endoscopic retrograde cholangiopancreatography (ERCP) is the gold standard investigation and intervention for acute cholangitis as it allows decompression of the biliary system through sphincterotomy or stent placement. This is often preceded by non-invasive imaging modalities such as CT abdomen or magnetic resonance cholangiopancreatography (MRCP) if available.
For further information read the Geeky Medics guide to acute cholangitis and the following article discussing the differential diagnosis: biliary colic vs cholecystitis vs cholangitis.
Case study 2
A 28 year old primip is currently 37 weeks pregnant and presents to the emergency department with heavy vaginal bleeding and severe abdominal pain. She has had an uncomplicated pregnancy up to this point and has no relevant past medical history. She has been diagnosed with placental abruption.
After initial resuscitation, she is clinically deteriorating and remains haemodynamically unstable. Her temperature is 37.3°C, respiratory rate 24 breaths/min, pulse 112 bpm, oxygen saturation 98% in room air, and BP 98/65 mmHg.
Interpret the patient’s blood tests using a structured approach. This will be followed by a discussion on the clinical reasoning behind the case.
Blood test results
Full blood count (FBC)
| Test | Result | Reference range |
| Haemoglobin (Hb) | 85 | ♂ 130 – 180 g/L ♀ 115 – 165 g/L |
| White cell count (WCC) | 15.5 | 3.6 – 11.0 x 109/L |
| Neutrophils | 11.16 | 1.8 – 7.5 x 109/L |
| Lymphocytes | 3.6 | 1.0 – 4.0 x 109/L |
| Monocytes | 0.4 | 0.2 – 0.8 x 109/L |
| Eosinophils | 0.3 | 0.1 – 0.4 x 109/L |
| Basophils | 0.04 | 0.02 – 0.10 x 109/L |
| Platelet count | 85 | 140 – 400 x109/L |
| Mean cell volume (MCV) | 82 | 80 – 100 fL |
| Reticulocytes | 4.1 | 0.2 – 2% |
Urea & electrolytes (U&Es)
| Test | Result | Reference range |
| Sodium (Na+) | 140 | 133 – 146 mmol/L |
| Potassium (K+) | 5.2 | 3.5 – 5.3 mmol/L |
| Urea | 7.6 | 2.5 – 7.8 mmol/L |
| Creatinine | 72 | ♂ 59 – 104 μmol/L ♀ 45 – 84 μmol/L |
| eGFR | 101 | >90 ml/min/1.73m2 |
Liver function tests (LFTs)
| Test | Result | Reference range |
| Alkaline phosphatase (ALP) | 78 | 30 – 130 U/L |
| Alanine aminotransferase (ALT) | 30 | ♂ <41 U/L ♀ <33 U/L |
| Aspartate aminotransferase (AST) | 28 | 1 – 45 U/L |
| Bilirubin | 13 | <21 μmol/L |
| Gamma-glutamyl transferase (GGT) | 30 | ♂ <60 U/L ♀ <40 U/L |
| Albumin | 36 | 35 – 50 g/L |
CRP
| Test | Result | Reference range |
| C-reactive protein (CRP) | 115 | <5 mg/L |
Coagulation screen
| Test | Result | Reference range |
| PT | 23 | 10 – 14 seconds |
| APTT | 53 | 24 – 47 seconds |
| Fibrinogen | 0.7 | 1.5 – 4.5 g/L |
| Ddimer | 1750 | < 500 ng/mL |
Interpretation
| Test | Interpretation |
| FBC | normocytic anaemia, neutrophilic leukocytosis, thrombocytopaenia and raised reticulocytes |
| U&Es | normal |
| LFTs | normal |
| CRP | elevated |
| Coagulation | low fibrinogen, prolonged APTT, prolonged PT and raised d-dimer. |
| Overall impression | disseminated intravascular coagulation (DIC) |
Explanation
Full blood count (FBC)
The full blood count shows normocytic anaemia secondary to placental abruption and haemorrhage as per the stem. There are raised reticulocytes which may be related to pregnancy, blood loss or degradation of RBCs. A neutrophilic leukocytosis is also seen suggestive of infection and/or inflammation.
Useful link: Geeky Medics | Full Blood Count | Interpretation Guide
Urea & Electrolytes (U&Es)
Normal.
Useful link: Geeky Medics | U&Es | Interpretation Guide
Liver function tests (LFTs)
Normal
Useful link: Geeky Medics | LFTs | Interpretation Guide
CRP
The CRP is elevated suggestive of infection or inflammation.
Coagulation screen
The coagulation screen is grossly abnormal and shows low fibrinogen, prolonged PT and APTT and a raised D-dimer.
Useful link: Geeky Medics | Coagulation Screen | Interpretation Guide
Overall impression
The patient is carrying a term pregnancy and is experiencing heavy vaginal bleeding and abdominal pain. Given this has been an uncomplicated first pregnancy up until this point with no relevant past medical history, it would be prudent to assume placental abruption as a diagnosis.
The patient is haemodynamically unstable following initial resuscitation in the emergency department and is clinically deteriorating.
Her blood results show a normocytic anaemia and raised reticulocytes consistent with significant blood loss from abruption. A neutrophilic leukocytosis is also evident as well as a raised CRP both consistent with inflammation and/or infection. Infection is a possible cause for the placental abruption.
The coagulation screen is grossly abnormal and shows low fibrinogen, low platelets and prolonged PT and APTT. This is likely the result of blood loss and secondary consumptive coagulopathy. D-dimer in this case is also raised which is in keeping with pregnancy but also with fibrinogen degradation products.
The abnormal coagulation points to a diagnosis of disseminated intravascular coagulation (DIC) secondary to placental abruption.
A typical blood picture of DIC includes:
- ↓ platelets
- ↓ fibrinogen
- ↑ PT & APTT
- ↑ fibrinogen degradation products (D-dimer)
- schistocytes due to microangiopathic haemolytic anaemia
Management of an antepartum haemorrhage due to placental abruption includes a rapid ABCDE assessment and resuscitation. Maternal resuscitation should not be delayed to determine fetal viability. At term, delivery should ensue either vaginally or if foetal distress via immediate emergency caesarean section in order to stop the bleeding.
DIC is a medical emergency and carries with it high morbidity and mortality. Bleeding and clotting should be controlled by means of fresh frozen plasma (FFP), cryoprecipitate replacement and/or platelet transfusion as required.
For further information read the Geeky Medics’ guide to placental abruption and disseminated intravascular coagulation.
Case study 3
An 83 year old man presents to his GP with a 4 week history of fatigue, shortness of breath and back pain. He has a past medical history of atrial fibrillation and takes bisoprolol and apixaban regularly. He does not drink alcohol and has never smoked. On examination, he appears pale, cachectic and has splenomegaly. His temperature is 37.9°C, heart rate 70bpm (regular), blood pressure 110/85 mmHg, respiratory rate 20 breaths/min and saturations 95% in room air.
Interpret the patient’s blood tests using a structured approach. This will be followed by a discussion on the clinical reasoning behind the case.
Blood test results
Full blood count (FBC)
| Test | Result | Reference range |
| Haemoglobin (Hb) | 110 | ♂ 130 – 180 g/L ♀ 115 – 165 g/L |
| White cell count (WCC) | 7.7 | 3.6 – 11.0 x 109/L |
| Neutrophils | 4.2 | 1.8 – 7.5 x 109/L |
| Lymphocytes | 2.76 | 1.0 – 4.0 x 109/L |
| Monocytes | 0.4 | 0.2 – 0.8 x 109/L |
| Eosinophils | 0.3 | 0.1 – 0.4 x 109/L |
| Basophils | 0.04 | 0.02 – 0.10 x 109/L |
| Platelet count | 115 | 140 – 400 x109/L |
| Mean cell volume (MCV) | 85 | 80 – 100 fL |
| Blood film | Rouleaux seen |
Urea & electrolytes (U&Es)
| Test | Result | Reference range |
| Sodium (Na+) | 139 | 133 – 146 mmol/L |
| Potassium (K+) | 4.9 | 3.5 – 5.3 mmol/L |
| Urea | 9.6 | 2.5 – 7.8 mmol/L |
| Creatinine | 182 | ♂ 59 – 104 μmol/L ♀ 45 – 84 μmol/L |
| eGFR | 31 | >90 ml/min/1.73m2 |
Liver function tests (LFTs)
| Test | Result | Reference range |
| Alkaline phosphatase (ALP) | 150 | 30 – 130 U/L |
| Alanine aminotransferase (ALT) | 32 | ♂ <41 U/L ♀ <33 U/L |
| Aspartate aminotransferase (AST) | 31 | 1 – 45 U/L |
| Bilirubin | 15 | <21 μmol/L |
| Gamma-glutamyl transferase (GGT) | 40 | ♂ <60 U/L ♀ <40 U/L |
| Albumin | 38 | 35 – 50 g/L |
CRP
| Test | Result | Reference range |
| C-reactive protein (CRP) | 53 | <5 mg/L |
Bone profile
| Test | Result | Reference range |
| Corrected calcium | 2.98 | 2.2 – 2.6 mmol/L |
| Phosphate | 1.4 | 0.8 – 1.5 mmol/L |
| Alkaline phosphatase (ALP) | 150 | 30 – 130 U/L |
| PTH | 1.0 | 1.6 – 6.9 pmol/L |
PSA
| Test | Result | Reference range |
| PSA | 1.6 | <4.0 μg/L |
Serum electrophoresis
| Test | Result | Reference range |
| Serum electrophoresis | Monoclonal paraprotein band detected | – |
Coagulation screen
| Test | Result | Reference range |
| PT | 10 | 10 – 14 seconds |
| APTT | 25 | 24 – 47 seconds |
| Fibrinogen | 3.0 | 1.5 – 4.5 g/l |
Interpretation
| Test | Interpretation |
| FBC | normocytic anaemia with thrombocytopaenia and rouleaux seen |
| U&Es | reduced eGFR |
| LFTs | raised ALP |
| CRP | elevated |
| Bone profile | hypercalcaemia and low PTH |
| PSA | normal |
| Serum electrophoresis | monoclonal band detected |
| Coagulation screen | normal |
| Overall impression | multiple myeloma |
Explanation
Full blood count (FBC)
Normocytic anaemia with thrombocytopaenia and rouleaux seen on blood film. This is due to accumulation of malignant plasma cells within the bone marrow suppressing normal production of blood cells.
Useful link: Geeky Medics | Full Blood Count | Interpretation Guide
Urea & Electrolytes (U&Es)
Abnormal plasma cells produce paraproteins, which accumulate in the kidneys, causing renal damage. This leads to raised creatinine and a reduction in eGFR and, therefore, an acute kidney injury. There is no mention in the stem of chronic kidney disease although this should be considered due to patient age. Hypercalcaemia also contributes to renal damage.
Useful link: Geeky Medics | U&Es | Interpretation Guide
Liver function tests (LFTs)
Isolated elevated ALP secondary to likely bony lesions.
Useful link: Geeky Medics | LFTs | Interpretation Guide
CRP
Mild elevation of CRP can be seen in inflammation, infection and malignancy.
Bone profile
His bone profile is grossly deranged. Hypercalcaemia is seen due to osteoclast activation by paraproteins produced by the plasma cells. This prompts the release of calcium from bone. ALP is raised as seen in LFTs. PTH is low due to feedback mechanisms from elevated serum calcium.
Useful link: Geeky Medics | Bone Profile | Interpretation Guide
PSA
PSA is normal.
Serum electrophoresis
Malignant plasma cell replicates to produce clones which in turn overproduce a single immunoglobulin. This produces a monoclonal band on serum electrophoresis.
Overall impression
This patient is presenting with fatigue, back pain, weight loss and shortness of breath over 4 weeks. He has a low grade fever but other vital signs are acceptable. Important differentials include multiple myeloma, lung cancer and prostate cancer. In this patient’s case, interpretation of his blood results is indicative of multiple myeloma.
The full blood count shows a normocytic anaemia, thrombocytopaenia and rouleaux on blood film. The patient has hypercalcaemia and subsequent low PTH driven by it’s feedback loop. A monoclonal band has been identified on serum electrophoresis in keeping with multiple myeloma. Reduced eGFR is a consequence of the paraprotein produced by the plasma cells and the resultant hypercalcaemia.
This patient should be admitted for their AKI, electrolyte disturbance and medical review with regard to their new multiple myeloma diagnosis.
For further information, read the Geeky Medics’ guide to multiple myeloma.
